I think reasonable feminists can discuss 1) whether some statements or actions by Obama, cited in this video, were intended to be sexist and 2) whether a candidate should be held accountable for everything his supporters say. I also assume that McCain supporters are responsible for some of the blatant sexism against Clinton.
But here's what I think is indisputable: Some Obama supporters have exhibited blatant sexism. Obama should come out and say that sexism is wrong. This could help heal divisions in the party.
I know that Obama supporters believe that Clinton and her supporters have said things that feed racism. See my points 1) and 2) above. Whether Obama supporters believe her or not, Clinton has spoken against racism many times in her life. If Obama has addressed sexism at length or apologized for the sexism of some of his supporters, I would (sincerely) like the citations.