Given that Buddhism could accommodate people's prior religious beliefs, why is Buddhism itself now described as a religion?

Nyom veenusAV,

It's probably a believe and rendering of communist, socialist that the Buddha "advocated for education to all humankind without considering...". We already know that outcome called "Khmer rouge", (Khmer, pali khema, "person or land at peace", epic for Arahat), to give one of many samples, by adding red to wise, desire/aversion to calm.

As he told, his teachings are just for those "ready to be tamed" and of course it is a strong religion (i.e. binding, robe to something), but without an idea of "re" like others may advertise with certain anchors for pride. One hasn't been bond to liberation before the path to master.

So if one calls it "ligion", such would be probably better.

Is Buddhism has more affinity towards a free-thinking society...

The Buddha did not much care about ordinary society but only for his Re-ligion, Legion, the Sangha. Although he was open for good individual advises, he had neither the idea to lead nor to feel responsible for what societies are doing or not.

He also taught on and on on how one should thinks, even on what, so it can not be said at all that the Sublime Buddha was a "(Pseudo-)liberalist" but one who gave strict advises on how to gain real liberality.

And he rebuked the Scientist very often and he taught of what one should incredible fear and what not.

Since it is a very black and white way out of Samsara, his Dhamma will probably not fit even a little to modern ideas. It's just that trades are good in selling new things people are not able yet to know it a original or a market-fake.

As for Buddhism, that is housholder-stuff... they love to build their own things and sand-castles.

(Note: this is not given for Buddh-ism, exchange, stacks, trade and gain binding to world and common societies but for liberation)

Since Buddha advocated for education to all humankind without considering race or color, will it be like a revolutionary thought came before centuries (like communism, socialism ...)?

Yes, the Dharma taught by the Lord Buddha was definitely revolutionary at his times, hence all the knowledge pertains until this day.

But most of the world refers to it as a religion. Is it because of the transformation to idol based community from a spiritual community created by Buddha?

Over thousands of years, the preach have transformed and therefore arrives at different "Schools". But what is an Idol? Is a teacher an Idol? And if one follows a good teacher's teachings, does that equate to worshiping an Idol?

Does Buddism has more affinity towards a free-thinking society based on modern science OR towards a ritual-based society based on fears that remind the mind to do good acts?

Neither.

The gap in principle between Science and Dharma is "Drive a conclusion base on what everyone can visually see" VS "do not drive a conclusion based on only what everyone see".

The freedom in the Dharma is freedom from Dukkha. Not absolute freedom to do anything one wishes.

The teaching is not to inflict Fear, but do speak of the truths. Doing good deeds as a means to be "skillful" and noble, not because purely out of fear. (although there are some who only do good deeds out of fear, but that is not the point)

Re. whether it's revolutionary socialism, yes and no:

• Yes the Buddha in the suttas challenged some conventional/social hierarchies, especially the idea that someone (e.g. a Brahmin) is or isn't holy because of their social caste.
• But no I think that the Vinaya obviously makes an effort (several efforts) to not cause conflict with lay society -- don't break the "king's laws", and regulations about when and how to go on alms rounds, and asking parents before ordaining, etc.
• Also I think it's meant to help everyone, universally -- not just help the poor, or help the rich, or the priests or the warriors, or the men, or even only the human beings.

Re. whether it's called a religion, does it matter what it's called? What else would you call it, what do you call "mathematics" for example (art, science, practice, doctrine), or what do you call "family" (society, way of life, relationship, vehicle)? I guess it's called a religion because it shares some properties with "religions" (or "other religions"), for example:

• Belief, faith, confidence.
• Moral/social rules
• Soteriological theory, a doctrine of liberation or salvation
• Uniforms (at least in monastic society), and rituals, special places, special days

I guess it's called that because people like to generalise or classify, make analogies (e.g. "X is like Y") and reuse existing words (like "religion") -- especially when thy encounter something new, they might want to compare it with what they "know" already.

Also some of the things I mentioned (e.g. ritual, uniform, the iconography and architecture of special places like temples) is public and visible -- and that's what (perhaps that's all that) someone who is not a Buddhist will see. Even more so if they don't know any Buddhists.

And if Buddhism is mental practices, states of mind -- not only rituals -- maybe that's less evident to the world at large. Maybe it's not even considered uniquely Buddhist (e.g. you might think of someone, you might recognise that, "he's a kind person", instead of, "he's a Buddhist").

As with anything else, that completely depends on what you consider a “religion” is, or what is a “religious belief”.

When westerners first came in contact with Buddhism they considered it a “philosophy” as they could not conceive of a religion that did not have a “god” at its center. The idea of an atheist religion did not make sense. You can see that such bias still exists in modern dictionaries.

But when does a philosophy become a religion and when is a religion a philosophy? Is Nihilism a religious idea or a philosophical one? What about philosophical skepticism? Can science itself be considered a religion?

Although Buddhism is very flexible and personal, it is very clear that to progress in the Buddhist path you have to accept a set of beliefs (e.g., Samsara and the eight-fold path) and reject others (e.g., atman/soul ). It is possible to enter the path while still holding to incompatible beliefs, however sooner or later these beliefs will conflict with the teachings.

It is also very hard for most people to let go of the idea of a “god”, of atman, and many others. This sets a limit to progressing on the path.