As counterpoint, though, I've heard some absolutely bonkers impressions of the US made by some Europeans. And that's not isolated; there seem to be lots of Europeans who have some very strange ideas about what it's like in the US.
I do agree with your general point, though: I would expect your average European to have a better understanding of the politics of the US than your average American would have of even a prominent European country like Germany.
Totally, it happens everywhere. And there are stereotypical traits in every country. It's just that everybody tends to recognise the US ones, but nobody knows them for all the other countries. A random European cannot say "this is soooo typical of Latvia".
But a random European can easily say that the parent is sooo stereotypical of the USA :-).
Note that I believe there is some level of European identity. But "European condescension" is not really part of it, I would say. What the OP may have felt was maybe some "non-US condescension"? I think it could be a thing. The OP said "believe me I know Europe better than you, because I live in Europe AND I am an American" (which somehow implies that being an American made them more knowledgeable? Not sure). The answer was something like "dude, it's so American to believe and proudly say that you must know better because you are American", I felt. Sure, it's condescending. But I don't think that whatever the European shared identity is contains a "they are condescending against anyone non-European".
I do agree with your general point, though: I would expect your average European to have a better understanding of the politics of the US than your average American would have of even a prominent European country like Germany.