I recall Breitbart having some damning articles against minorities but I don't remember the specifics. So while I think you're right I'd be rather interested in some proof that Bannon is pro Nazi / KKK. Otherwise I'm thinking at worst he has encouraged them and may have some overlap.
https://www.splcenter.org/stephen-bannon-has-no-business-white-house
^ That summary accurately reflects what I remember of Breitbart. I probably have a more pragmatic approach to realizing who they are, and how they ended up encouraging white supremacists. It starts with simple human tribalism. Democrats VS Republicans. And who do minorities overwhelming vote for? So in a world of partisanship minorities are automatically considered a Democrat. Automatically "the enemy". Identity politics being what it is, there are minority issues brought up as national issues. But again, those belong to Democrats. So to campaign against Democrats, they will campaign against minorities and minority issues. It's racism derived through petty party politics.
Does it ultimately matter? It means there is hope to divest them from their entanglements. While they're dead set towards partisanship and attacking Democrats, it means they're not necessarily dedicated to attacking minorities. Even though the two separate "causes" are often interchangeable. The crux of it: Is fighting the good fight more important than condemning white supremacists? Bannon may be willing to call them clowns, but would he really ACT against them? To condemn not with words but with actions?
He may view them as idiots, but he may be viewing them as useful idiots. And that's a problem. Ultimately Breitbart, Bannon, Trump and company should be held responsible for this overlap, for this encouragement. It's one thing to call #BLM out for its foundation of lies, it's quite another to talk !@#$ about minorities. To paint them as an enemy. To add fuel to the fire.
America needs to stand above that. But how do we claw it back now? What actions do we want Republicans to take to fix this?