Good god. This is the kind of thing my DH does - and is hardly a white supremacist (his mother is a Hispanic immigrant). He's fascinated by the shit these people put out and can't believe others actually believe it. Hardly a day goes by where he doesn't regale me with the latest absurdity. He also finds funny/stupid stuff like
The Crazy Nastyass Honey Badger original narration by Randall on YouTube.
https://www.youtube.com/watch?v=kb6bWsa_LdQ
I can't understand why you would even have a glimmer of suspicion about your DH unless, deep down, you know he agrees with the sentiments he finds on those sites. I have no doubts about why my DH is reading them.