What bothers about the "she wanted it too much" argument, in addition to the points already made above, is that Affleck was just as bad as she was this year (and I say that as a fan of his). And yet he's generally praised for his neediness and desire for outside validation -- I've seen a lot of, "He's adorable and he deserves the Oscar, idgaf what you say," arguments -- whereas she's uniformly criticized.
In complete contrast to Affleck, even people who agree that she deserved the Oscar criticize her desire for it, and I do think that for a lot of people, one of the underlying reasons is that women are held to a different standard.