There are many factors that play here. Having lived in many Western European countries, I think Czechs are in general not substantially more racist than French or Italians. However, contrary to other countries, we have no filter. Here, people say what they think (and sometimes even what they actually don’t - just to piss you off, shock you, or simply because it’s forbidden). That has several reason, some of them you mention (there are not many Black people to offend anyway). We also historically have a very strong opinion about censorship and about when someone is telling us what to think - and I’m not only referring to Communism, it dates far back. We have a general “no a co, tak se z toho nepo***” attitude, which expects you not to get offended easily. And finally and maybe most importantly, we (and rightly I think) feel zero responsibility towards Black people (and basically towards anyone haha) because we were never involved in slavery and never had colonies. So the BLM movement is really not helping here, because most Czechs will only get pissed if you expect them to excuse/knee/change their attitude, because of something they never did. But at the end of the day, if you speak the language, drink the same beer, sit in the same pub, tell the same jokes, Czechs will actually forget where you came from quite fast. As evidenced by the relatively very successful integration of 2nd generation Vietnamese (who in sum, we all pretty much love).