In his 1000 subscriber Q&A he answers this question, here's what he says in that video:

"It's not that I'm such a big fan of the SPD in the 20s and 30s, they weren't really the good guys either in a lot of cases, It's just that I'm a fan of history and like the idea of people coming together to fight for democracy against the forces that try to destroy it."

i dunno if he's said anything more recently, I just remembered this but I haven't been subscribed to him in a while.