American conservatism(at least the current populist movement) is considered radical extremism in the eyes of the rest of the world.

Western Europe doesn’t lean left, they are firmly left as is China, India and Oceania. Considering that encompasses over 2/3rds of the global population I think most would probably agree. I’m not sure what part of the American center you think is further left than average but I’m going to guess that you are focusing on a few select issues that you don’t agree with and assuming everyone but the crazy American liberals agrees with you. Most countries are extremely socially liberal and the ones that aren’t are known to be ruled by violent and oppressive regimes.