It's called free will for a reason. If you want someone to love you, they have to also be free to not love you, and to hate you. For good reasons or bad reasons or no reasons. Because someone shot their dog, because they shot someone else's dog and can't find their way to forgiveness yet. Because they were taught an evil and mean god, blame him for all their troubles and want to get back at him. Because their family has abandoned them and they can't think of "father" without hating.
All of these are explanations and reasons, but they are not excuses.
We have choices, our choices matter: to us and to others we can or do impact. What we do has consequences and we are responsible for them. We are instruments of God's love or of our own hate.
God showers us with light and love, sometimes we see it, sometimes we don't. Sometimes we listen; sometimes we don't. Sometimes we remember, sometimes we forget.
I've never met anyone who didn't want to be loved and to love. And I've never met anyone who was denied love, God's love included, except by their own choice. This is also true for me.
"Free to love; free to hate" is a package deal. And you get what you give. By choice. God loves everyone, and respects their choice. Without that, no love, of God or otherwise, is possible.
What is it about one man that causes him to choose to believe and what is it about another man that causes him to not believe?
Is one guy more pious, more holy, more intelligent, better looking than the other guy?