As to the issue, gay actors have played straight roles all along without bitching and moaning about it. It's acting, you're being paid to lie and pretend. If you can't handle a gay sex scene, but don't raise the same objections with straight ones, find another line of work.
What's next from you? Women should be required to show it all during sex scenes? Topless? Show some ass? If they don't like it then can find another line of work, right? Gotcha.
Do you think that hasn't happened a lot? If the story/plot calls for nudity, unless you are a major star, you either do it or find other work.
You just said it - "find other work". I agree. But I don't agree with "find another line of work". He's free to choose which roles he wants to play within his profession. If he doesn't like the role it doesn't mean he needs to find a new line of work.