To me as a European, posts and comments about US politics can be very confusing. There’s the different interpretation on the word liberal you mentioned. There’s also the fact that the colours are reversed: here red is for the left - socialists and communists - while blue is the liberal right (not so much conservative right, though there are conservative subgroups of the “blues”). And there’s the fact that they often assume familiarity with political events and people unknown to me.

Somewhat related: posts and comments from the far and extreme left are often even more incomprehensible. They seem to have their own language entirely.