So, does Allen play a homosexual in the film? I don't think so. He's an actor. He acts the role he is given in the film.
The film stands for itself. What Allen says outside of the film is irrelevant. It is the character he plays in the film that is relevant.
Gay actors play straight roles. Straight actors play gay roles. That's their job.
We should ignore this entirely, and let the film speak for itself. From all accounts, it's a good depiction of what actually happened.
Sadly, this is not true. We don't live in a vaccuum. If our kids want to see this film, and then learn more about the actors, where do we stop them? Where does the information flow end? If they believe the story on the screen, they will likely believe the story being told on any screen, TV, etc.