Awwwww i liked Adam on the show! but yeah...as an actor he should be prepared for these kinds of roles. However, the writers have to keep in mind what their actors are willing to do etc etc. This particular actor was a very poor choice. I think Thad Luckinbill on the show would have been a better choice. He's done gay scenes before and seems more open to it. But i don't think he's homophobic just because he doesn't want to do it. It's unprofessional, but no one knows how he, as an individual feels about the topic.
I didn't really watch the whole season, but i watched the last two, and i thought both of them are really talented. No matter what Adam is going to get a record deal, and he's already famous anyways, so their both winners in a respect. AI isn't always fair, no competition is. But its not like Kris winning was a total steal. Kris has a damn good voice. So it doesn't all have to do with Adams sexual orientation.
...but even so it would still be hideous.