Nasty. However just because someone is taken up by violent thugs, doesn’t mean their work is to be ignored.
I had a friend who was an impassioned Marxist and socialist. He loved Wagner’s operas and was very interested in Nietzche’s philosophy, anti-semites both.
Steiner’s ideas are unhelpful for quite other reasons. He did however believe learning disabled should be educated in the same system as ordinary children and were to be treated with respect. I was shocked when I briefly volunteered to help at a local council home for learning disabled children how they were treated – not with any cruelty but not to be taken seriously.
The Nazis, of course, would have regarded them as decadent and destroyed them.