Why do people think that their desires are entitled to approval?

A recent question about homosexuality in ancient Greece got me to thinking

I think if there is a lack of good communication about homosexuality these days, it is not so much that people want to actually stop people from having homosexual relationships. I think most heterosexuals are too focused on their own lives than to worry about what other people are doing in their proverbial bedrooms

I think it’s that some heterosexuals get the idea that it is not enough to simply tolerate it.

It is the implication that unless they actually approve of it, they are bigots.

But the truth is some people do not approve of it, just like, even though it is legal, some people do not approve of divorce.

Why isn’t tolerance enough?