I used Brokeback Mountain as an example because there is no clear cut reason why it shouldn't be in school plays, yet we all realize that it would be inappropriate. Is it the fact that it depicts a sex act, maybe. Is it that it has a history of being controversial, maybe. Is it that there is no real reason homosexuality should be a topic or theme in a school setting, maybe. There are a lot of questionable reasons, so it's best to just not do it. But it's going to ultimately be up to the dojo whether they want to teach blind students, and if they decide to make that choice, more power to them.
Well, aside from the main topic: at least here in Germany, there is absolutely no reason why homosexuality shouldn't be a topic in a middle school play. Maybe not with the children, they probably wouldn't understand it, but he older children? Although maybe you wouldn't choose Brokeback Mountain but rather something a little closer to their reality. But showing that it's okay to be different is important, and that goes for homosexuality as well as for race or whatever...