Nitpick … JFK was not a “Brahmin” — the term Boston Brahmin specifically excluded Irish Catholics. And again, his family’s success in the past didn’t matter. He annoyed a lot of people by not being part of their tribe, or the usual tribe that participated in US national politics, anyway.
I think that 3/4 of the hatred of Obama comes from raw tribalism. If he smashed ISIS, ended all wars in the Middle East without killing a single soul, made for the employment of every American that wanted a job, he’d still be hated.
Me? He makes me happy. I’m not a WASP. The more diversity there is in American politics, the more chance my children (or grandchildren), if I choose to have them, will have for success in this arena.