I don't know that young women who idolize these stars will ever be able to see them the same way again. But I do worry about young folks and what they are being taught - America is racist, we torture prisoners and wiretap Americans, etc.
One ad I saw had a byline for the film, something like "love is a force of nature." In other words, people can't control their urges and have to do whatever feels good. Except, of course, if childrens' behavior conforms to traditionally understood sex roles. Then that behavior is not a "force of nature," but a result of the bad old American society and needs to be fought. Sheesh!
Personally, I like Jake Gyllenhaal. I've seen him in a number of movies, such as "Proof" and "Donnie Darko". It really unnerves me that he has made the decision to act in Brokeback.
You're right, I'll never be able to watch this talented kid in a movie without thinking, "ick".