For main response to Grabowski and Klein see here. This post covers the Wikipedia Icewhiz who is the principal source and driving force behind Grabowski and Klein’s article. Since this is a long story, this part covers events only up to Icewhiz’s topic ban on Wikipedia from all articles related to Poland and the Holocaust. Please read the footnotes at the end for links and evidence as well as additional interesting information.
Ruin a person's reputation, not accusation.
The name of the article was "A History of the Palestinian People", not "A Brief History of the Palestinian People"; the rest is correct.