Does downvoting an answer qualify as divisive and harsh speech?

Yes it is. It's hardly to assume that any here isn't lead by unskilful mind using it and what ever system is build to serve common people successfully requires to make use of greed, aversion and ignorance. Well, and people here are foremost devoted and feel obligated to serve Mara. At least lazyness to write, and fear to get rebuked or different punished by system-servers, will lead one to make use of it either and so, in best common way, mixed kamma will be always the peak of skillful use of vote.

At least, to do not fall into other foolish views, it's totally not generally that dispraise and rebuke is wrong speech, but leads even to heaven if right and proper investigated, but as for the ordinary person, not arrived at the Dhamma, naturally corrupt, either praise, blame and equanimity will be in 95% of cases akusala.

"Dhammo have rakkhati dammacāriṁ"

Hard would it be, if even searching for, to appear in good companionship...

(and sure, one is free to up- downvote here, or confused just walk on, or gain conviction by catching proper attention, watching foremost the frames of reference)

These are concerning public dhamma discourse and what is abusive circumstance

There Venerable Sāriputta addressed the mendicants:

“That is possible.”

When he said this, Venerable Udāyī said to him, “This is not possible, Reverend Sāriputta, it cannot happen!”

But for a second … and a third time Sāriputta repeated his statement.

And for a third time, Udāyī said to him, “This is not possible, Reverend Sāriputta, it cannot happen!”

Then Venerable Sāriputta thought, “Venerable Udāyī disagrees with me three times, and not one mendicant agrees with me. Why don’t I go to see the Buddha?”

Then Sāriputta went up to the Buddha, bowed, sat down to one side, and said to the mendicants: That is possible.”

When he said this, Udāyī said to him, “This is not possible, Reverend Sāriputta, it cannot happen!”

But for a second … and a third time Sāriputta repeated his statement.

And for a third time, Udāyī said to him, “This is not possible, Reverend Sāriputta, it cannot happen!”

Then Venerable Sāriputta thought, “Even in front of the Buddha Venerable Udāyī disagrees with me three times, and not one mendicant agrees with me. I’d better stay silent.” Then Sāriputta fell silent.

Then the Buddha said to Venerable Udāyī, “But Udāyī, do you believe in a mind-made body?”

“For those gods, sir, who are formless, made of perception.”

“Udāyī, what has an incompetent fool like you got to say? How on earth could you imagine you’ve got something worth saying!”

Then the Buddha said to Venerable Ānanda, “Ānanda! There’s a senior mendicant being harassed, and you just watch it happening. Don’t you have any compassion for a senior mendicant who is being harassed?” https://suttacentral.net/an5.166/en/sujato

Downvoting, pestering, contradicting and annoying the righteous is like that. It is wrong action.

"The practice of Dhamma, [1] the practice of continence, [2] mastery of this is said to be best if a person has gone forth from home to the homeless life. But if he is garrulous and, like a brute, delights in hurting others, his life is evil and his impurity increases.

"A quarrelsome bhikkhu shrouded by delusion, does not comprehend the Dhamma taught by the Awakened One when it is revealed. Annoying those practiced in meditation, being led by ignorance, he is not aware that his defiled path leads to Niraya-hell. Falling headlong, passing from womb to womb, from darkness to (greater) darkness, such a bhikkhu undergoes suffering hereafter for certain.

"As a cesspool filled over a number of years is difficult to clean, similarly, whoever is full of impurity is difficult to make pure. Whoever you know to be such, bhikkhus, bent on worldliness, having wrong desires, wrong thoughts, wrong behavior and resort, being completely united avoid him, sweep him out like dirt, remove him like rubbish. Winnow like chaff the non-recluses. Having ejected those of wrong desires, of wrong behavior and resort, be pure and mindful, dwelling with those who are pure. Being united and prudent you will make an end to suffering." https://www.accesstoinsight.org/ati/tipitaka/kn/snp/snp.2.06.irel.html

These are some of the harshest reprimands in the sutta.

I do not think downvoting is harsh speech. This is a Q&A platform that individual should allow to post their opinion.

With good intention and no harsh remarks, downvoting could be a wake up call to the question posted, improving the quality of the future questions.

Use it right, it is a good feature to have!

I doubt we’ll find a sutra reference that speaks about downvoting answers, so I’ll just relate a personal experience here. Early on, there was a person that downvoted seemingly every one of my answers for a period of time, and I found that very divisive, especially because his comments were not helpful, other than to let me know that it was he that was doing it. That kind of downvoting, in my opinion, does not conform to right speech. But this was contextual. If an answer misrepresents Buddhism in general, or is based on something else entirely, then downvoting that probably does at least conform to defending the Dharma, if not also being right speech.

Of these four persons, Potaliya, he who speaks both in dispraise of what deserves dispraise seasonably saying what is a fact and true and in praise of what is praiseworthy, saying seasonably what is a fact and true - he is the most admirable and rare.

AN 4.100

It's a well-known or frequently-expressed feeling on other SE sites -- a downvote feels like an insult, and a downvote without a comment seems rude and unhelpful.

Even so, in spite of the fact that users may not like it, SE allows it -- people can downvote, and aren't required to comment.

I recommend you comment -- if you can be friendly, and with a comment maybe phrased as a question or as constructive criticism suggestion -- especially with a new user, who might be sensitive to the community's reaction to their post.

I might also recommend that you don't comment in any of the following scenarios (if a comment is no better than or worse than no comment):

• If the comment isn't informative, for example:

  I"m downvoting this answer because of your view about X, which is wrong I tell you.

• If it's not new information:

  As I've told you 50 times already, I disagree with your view about X

• If experience tells you that commenting on this particular person's answer usually leads to more arguments and "division" than not commenting

I agree it may be perceived as harsh.

As for whether it breaks a precept, is immoral, I think that depends.

Canonically the Buddha would have "a sense of the proper time" for saying "things that are factual, true, beneficial, but unendearing & disagreeable to others" -- which most people don't necessarily.

But the Buddha might also sometimes not correct -- or stop correcting -- mistakes:

• Was the Buddha harsh?
• Why does the Buddha, in the Pali Canon, periodically engage in harsh speech?

I personally avoid downvoting and harsh comments unless it is extremely necessary because it hurts the sentiments of poster and vilifies the atmosphere. Buddha criticised many times but it was out of compassion. Those who try to be emotionless while judging have wrongly interpreted the teachings. The point is to be as considerate as possible while judging a human being... there is no substitute for a sincere compassion.

The purpose of upvoting and downvoting answers on this site is to give the community the chance to determine the quality of the answers.

So, the better the answer (in terms of being on-topic, correct, accurate, answers the question and supported by elaboration and references), the more upvotes it should get.

On the other hand, an answer which is on-topic and allowed (not spam, rude etc.), but is wrong or inaccurate, should get downvotes. In fact, I think it is beneficial to downvote wrong answers, so that readers are able to identify it as a negative example i.e. an example of wrong understanding.

Is it incorrect speech to downvote?

According to MN 58:

1. In the case of words that the Tathagata knows to be unfactual, untrue, unbeneficial (or: not connected with the goal), unendearing & disagreeable to others, he does not say them.

2. In the case of words that the Tathagata knows to be factual, true, unbeneficial, unendearing & disagreeable to others, he does not say them.

3. In the case of words that the Tathagata knows to be factual, true, beneficial, but unendearing & disagreeable to others, he has a sense of the proper time for saying them.

4. In the case of words that the Tathagata knows to be unfactual, untrue, unbeneficial, but endearing & agreeable to others, he does not say them.

5. In the case of words that the Tathagata knows to be factual, true, unbeneficial, but endearing & agreeable to others, he does not say them.

6. In the case of words that the Tathagata knows to be factual, true, beneficial, and endearing & agreeable to others, he has a sense of the proper time for saying them. Why is that? Because the Tathagata has sympathy for living beings."

I would say the third case above is the case for downvoting.

Downvoting an answer may be unendearing and disagreeable to the person answering.

If users can judge whether the correctness of an answer is factual and true, and if declaring this is beneficial for the answerer and other readers, then upvoting or downvoting is the proper time to express this, according to the way this site works. This is correct speech.

It's only incorrect speech if you know an answer to be correct, yet downvote it, or vice versa.