Accepting the simple answer of "they're just racists" isn't going to do anything good. It serves to make us feel better about saying "fuck em", but doesn't address their place in culture and how to combat them at all.
The alt-right is like people who are against polio vaccines because there's no polio in the world.
Their position is thus: "Who needs progressive action against racism when I already know all races are equally capable?..... only complaining nanny ideologues, that's who."
If someone is lying to themselves and lying to you, their interlocutor, the best course of action is not to enable them. The best course of action is to, first, call them out on their bullshit. You can then move on from there - at which point we are getting into jobs programs and the like that extend well beyond the confines of this thread.