Japan is a fairly ethnically and culturally homogeneous country. It is natural that they would expect Parisians to look and behave a certain way. When they don't, it is of course a big negative to many visitors - they come to Paris expecting a certain look and feel, a certain atmosphere and culture, but they are getting something else.

You do not need to be from Japan to feel that way when visiting Paris either. And I do not see anything wrong with pointing that out.

Here's how it sounds if worded more frankly: "Paris sucks. The transport sucks, bathrooms suck, food sucks, everyone's rude, and there's lots of immigrants."