I suspect there are two big difference between OP and many of the readers here.
At least for sure, Berlin vs most major US cities is night and day different in terms of commute and enjoyment opportunity. Berlin is a fun city full of things to do, places to eat, and clubs. Plus it's all accessible without a car.
Meanwhile, in the US, it's usually a very different story. Doing something after work often involves a much greater time cost, thereby reducing the likelihood that someone will partake of the opportunity. So office work is more likely just office work with no after-work fun.
Just like most people in the US have no clue what life is like in the big EU cities, most Europeans have no idea how different US life is. I've lived both, and I can say without question that it's easier to have a fun office+after-office experience in a city like Amsterdam or Berlin (or London probably) than Denver, Dallas, or most other big US cities.
OP likely doesn't factor this in and comes to the naive conclusion that it must mean we don't like talking to people.