It's part of the smear campaign the left has been engaging in since Trump announced his candidacy for POTUS. No one in his administration or circle of friends (or anyone who has said a kind word about him) is exempt. They will go after anyone they deem friendly to Trump.
RACIST?? He's worse
If the only people we had to confront were the David Dukes of the world, racism would be a whole lot easier to deal with. There aren't that many of them; they're mostly not very bright; and to give them their due, they actually believe what they're saying. That limits their political flexibility. Guys like Bannon are far more odious. He probably
doesn't believe most of the alt-right's nonsense. But he's willing to sit in the background and cynically exploit it for personal and political benefit. That's about as vile as you can get.