I think, Artiste, that the film is not anti-gay at all...perhaps 'honest gay' is a better word.
Much discussion has occured about the not-so-perfect characteristics of both Ennis and Jack, but these are not to be seen, I think, as anti gay. Rather, human frailties or imperfections that are endured by everyone.
If some viewers look, for example, at Ennis and Jack's adulterous affair as a means to cast negativity on being gay, it would be an unfortunate interpretation, and it would miss the point. While gay lifestyles, and Ennis and Jack's to some degree, are by nature usually different than the typical heterosexual family, director Lee and the writers clearly did not intend to create fodder for any anti gay sentiments. And I do not think it has happened unexpectedly either.