But almost all countries are more liberal than those two. My question isn't if the US and UK are the least enlightened countries in the world, but rather, if people see them as particularly enlightened among countries. Ie compared to any other random liberal country like Mexico or Czech Republic.

I understand OP's point, just curious whether the examples used reflect a common perception. To me when thinking of stereotypically enlightened societies, I think of Iceland or Canada or something. The US I think of more as a business+war society, and UK seems somewhere in the middle, but much lower than the rest of Europe.

This is based on nothing objective, just wondering what other people's perceptions of these places are