You tried this argument in the dedicated thread (now locked) and fell flat on your face.
Well, of course I did. How couldn't I, when you stubbornly insist on sticking to your own vision of what the series is about?
I really don't know what that quote is supposed to prove. Yes, they've written down some names, yes, they've clearly referenced Slavic architecture. That doesn't affect the way the game and the novels treat Slavic folklore. Which is largely superficially and it only played an even lesser role in the books, where the most overt cultural and mythological references are clearly taken from foreign regions.
I'm also not sure why you're giving me a history lesson, when I'm talking about the way they've adapted Slavic folklore. The world of The Witcher references real world history here and there, because Sapkowski is a history buff, but it does not focus on Poland or Slavic nations.
The Witcher did not become popular because people saw themselves or their history in satirical takes on foreign fairy tales and myths.
Anyway, this thread probably isn't the best place for this.