Like I said before- the message here is "don't do anything outside the norm". It was all a factor.
I can agree with some of that. I have never kept up with Idol - it just happens to be watched in my home so I hear some of it. If you look at the last three though, the guy who won and the guy who got voted off last week (I don't even know names) probably had the same audience - so that played a factor too. A three-way race where 2/3 have probably the same basic audience makes it difficult for the left-over person to overcome the numbers.
I can see more people voting multiple times for the guy who won though over Adam. From the beginning Adam was just a better entertainer and singer than anyone on the show but probably not prone to illicit hundreds or thousands of votes from the same person.
As far as Adam's orientation, that unfortunately played some role. However the American public is often dichotomous when it comes to entertainment. In the arts there are many high-profile gay artists that are wildly successful. Many were/are successful specifically because of their ambiguity. You could also look at someone like Madonna who mixed religious symbols with a very worldly and selfish message in probably the most profane ways possible (coming from a Christian perspective) and was still extremely successful.
Popular culture is filled with contradictions. The popular music industry is an area where talent is just a part of the equation. Look at who wins the Grammy's and tell me if those are always the most talented people in the industry.
Having said all that, I would probably buy Adam's album over anyone else in idol history. And I'm a social conservative, straight male who grew up and lives in the US mid-west