I think it's funny that so much of BDSM often plays on reactionary thinking. Communities centered around humiliation kinks are full of talk about how betas are genetically inferior for their immutable characteristics (like having a small dick), and should therefore be subservient to their superior alphas. I think it crosses the line when you start to bring racial fetishization into it, and I don't understand how a nazi kink would work other than being into the uniforms.