This whole line of discussion is weird - Stalinism and the USSR was the definition of anti-conservative and authoritarian. Literally ideologically leftist to a polar extreme in many ways.
I think the confusion stems from mislabeling and the cultural associations that some people have with it. In the US, the term socialist usually means something bad, while in Europe all modern states are build around some concept of democratic socialism.
If I say progressive, some people here might identify that with some mouth foaming marxist that will apologize any non free-market dictator.
Label progressive = human rights , not economic policy.
Any suggestion for a term that works better in your habitat is welcome!
Authoritarians come in all ‘colors’.