Do people have the ability to truly love God, without God guiding them into loving him?

I say yes to this question. God gave his only begotten son and that is all that really needs to be said. What other way can he show his love. He shows me his love everyday he is a constant fountain of goodness. We tend to let this material world stop us from seeing God's love. When you start to think about all you have to be grateful for it isn't long before you see how much God loves you. God gives us free will and it is your choice whether you love God or not. I choose to love my father and when I started doing that my life changed. Faith is what is not seen.

No, I don't think so.

1 John 4:19 (NIV1984)

We love because he first loved us.

This implies that all our love, toward God or anyone, only exists because His love comes directly to us or filters through other people to us. Extensive info at this commentary.

Regarding what I think I read from the rest of your question, God chooses to love the whole world, not just a select few:

John 3:16

For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life.

Here is how I would explain the viewpoint behind the comments you quote in your question. I do hold a belief about the nature of people that says that since the fall they are inherently bad, totally corrupt. This doesn't mean they were created that way, just that the corruption that we inherit from the first Adam is so complete that we can do nothing truly good or right on our own volition. This is commonly known as the doctrine of Total Depravity. You might check the entry on Theopedia, and articles such as this or this for an overview of how this doctrine is derived from Scripture.

Rather than defend that doctrine here, I simply want to point out that your question hinges on it. You ask:

So ultimately only a divine intervention can make a person love God?

To answer this, one possible way of defining what it looks like for a human to love God would be this way:

John 14:15
“If you love me, you will keep my commandments.

Yet if we apply this simple test to humanity and ask, "Do they keep his commandments?" we are left with the bleak conclusion that there are indeed none who keep God's commandments as God intended.

Romans 3:12
All have turned aside; together they have become worthless; no one does good, not even one.

Of course that isn't the end of the story. Again your question posed whether only a divine intervention can make a person love God. Christianity's answer to that is yes, and that divine intervention has taken place. That divine intervention is very poetically prophesied about in Ezekiel.

Ezekiel 11:19-20
And I will give them one heart, and a new spirit I will put within them. I will remove the heart of stone from their flesh and give them a heart of flesh, that they may walk in my statutes and keep my rules and obey them. And they shall be my people, and I will be their God.

This is grace. Unmerited favor: a divine intervention to transform undeserving fallen humans into creatures capable of loving that which they once hated.

There are of course Christian traditions that do not hold this view. Perhaps most notably, Catholicism has a different take on the issue. While they agree that man in his fallen state is incapable of doing any works that could affect his salvation apart from the Grace of Jesus, they disagree on how total the fallen state is concluding that the heart of men is not really dead to God, only wounded. While they understand salvation to be affected by God, they think man is capable of acting as an initiator in this process. Likewise several Protestant traditions hold that man in his fallen state is still capable of making some good choices.

In doing so, Reformed Theology would argue, they replace some aspect of grace with some aspect of works. If men can and do in their natural state "choose" to love God and that makes them eligible for salvation, salvation ceases to be purely a grace bestowed by God and his sovereign will in the matter becomes eclipsed by ours to whatever measure men are thought to be capable of deserving anything.