I've often found that when people say they can't relate to a gay character, what they really mean is that they don't like it and don't want to play one. I can't really think of any other reason why someone would have to object to playing as a gay character. As Qornea said, in the majority of games you don't really relate to the characters at all.
Not that I'm calling anyone out or anything. If you don't want to play a gay character, that's your choice. Just be up-front about it.







