Socialism

I agree with your takeaway, although the "extreme" definition is right next to it and is perfectly valid too. It's indeed interesting how loaded the word is by default.

3
a: very different from the usual or traditional : extreme
b: favoring extreme changes in existing views, habits, conditions, or institutions
c: associated with political views, practices, and policies of extreme change
d: advocating extreme measures to retain or restore a political state of affairs
the radical right