Maybe some are, but I guess most are not. -- Some people like this game a lot because it's a challenge and a huge and important part of japanese culture. Others might love to give it to their daughter. Others are "normal healthy heterosexuals" that just have fun to play as a girl on internet forums or video games.
A normal gay man is not interested in this game, because you can't play as a guy. Only as a girl - the only girl in a fantasy dream world of attractive young men. On the other hand, there might be some gay men that are not normal. lol.
So don't worry about it. Aren't we all a bit perv sometimes..?