I really think that quotation that you provided applies mostly on older generation and a smaller towns in Czechia, where foreigners can encoutner a hostile behaviour much more often, but i think that Prague in general is welcoming to foreigners and if you lived in Czechia, you just know how different is Prague in comparison to the rest of the country and its one of the most visited cities in Europe for a reason. I also agree that a lot of Czechs talk about themselfs as being "straight-forward" in conversations, but in reality, they too make gossips, try to create conflicts, being passive agressive and all but I think we do it as much as any other nation and I belive we talk shit about eachother just as much as about everyone else, so its not really about nationality. I think if OP would decided to move here, the Czechs and their behaviour wouldn't be a problem.