Maybe it's because personal experience is usually not enough to make such sweeping generalizations? All we know is this person liked the places they lived in Europe better than the places they lived in the US. But what about the places they haven't lived yet? European cities are not all the same. Similarly for US cities.
I have been in most capitals in Europe, and in quite a few cities of USA, and totally agree with the story. Of course there are some individual exceptions, but he is talking about the feeling from different cities, the state of public transportation or healthcare, which IMHO is fairly generalizable.
Our lives are not random samples.