I agree--that's why some of the parsing of voters really does nothing more than drive a wedge between the electorate. When we see the Blathering Heads waxing poetic about why women love Hillary, or why whites in Appalachia are rejecting Obama, or why blacks are going for Obama 9 to 1, it does nothing more than fuel division and lead to more of these sexist/racist charges and counter-charges.
Who in the world told you your vote for Obama was sexist? I haven't ever heard that particular charge lobed. There's been a lot of discussion about the treatment of Clinton by the media and many Obama supporters and the treatment of Clinton supporters, also by the media and many Obama supporters, but I have never heard anyone say that a person was sexist because they voted for Obama.
I won't accuse you of a red herring, or of latent sexism, but I do have to wonder. Unless you've got a link to when someone said that to you.