If a man or woman has sexual fantasies about children, so be it. If he or she doesn't act on them, that's the end of that. No harm done. People finding the thrill of murder alluring but resisting it; same story.

The difference is still that homosexuals tend to not harm people even if they act on their orientation. [Save for rape etc, of course.]

Back to the OP: I think whether sexuality is a choice is entirely depending on the cultural paradigm. The current one is very much pressuring on making a choice, though that differs per country. Modern self-identity is all about making choices, and I think that includes sexuality, so, yes, I would say the practice of a given sexual orientation is a choice.
I would like to add that it is in my belief true that the vast majority of people is per base psyche bisexual, though most are ignorant of this.

However, in Ancient Greece it was far different. Pansexuality was the norm in many of the city-states. There was no deviation, because most everything was socially accepted. Heterosexuality was still most common, but as an adult man it was also custom to watch teen boys undress and play with themselves after sporting. Their tendency to practice sports while nude has a lot to do with the sexual paradigm of that age. It was not a choice whether you were gay or straight; it simply was how it was. They didn't choose their sexuality like we do now, but simply their expression of it.