The Nazis advocated a welfare state for German citizens (able Germans of Aryan racial descent) as a means to provide social justice and eliminate social barriers between the German people.
Hitler claimed that equality of opportunity for all racially sound German males was the meaning of the "socialism" of National Socialism.
Part of the idpol SJW nonsense also comes from the old school SJWs, the actual nazis.
Völkisch equality: https://archive.is/wqw4J
No, it doesn't have anything to do with that.
Please read the essay to understand how it actually came about, it is well cited.
Yes, but my point is expanding what was said to an even earlier period.