Ironically, even the Waffen SS were appalled by the basic brutality of their Croatian "Allies". That region, and particularly the Serbs, were responsible for tying up hundreds of thousands of Nazi forces that could have turned the tide on the Eastern Front, and left us with a very different picture of life on this planet today. It would have increased the likelyhood that the Atomic Bomb would have been used in Europe against Nazi formations and/or population centers.
Of course that same region started the "War to end all Wars" (WWI) by some screwball Serbian anarchist killing the Hapsburg Heir to the throne. It seems to me that it's a good place to avoid.
In Donja Gradina alone Croatian Nazis a.k.a. Ustashas murdered more than 360,000 Serbs, Jews and Gypsies in the most bestial way.
However, the claim of USHMM is not surprising. During Bosnia civil war, USHMM was the venue of racist Anti-Serb activity ; Their belated admition of genocide commited by Croatian and Bosnian Muslim Nazis against Serbs, Jews and Gysies made construct "Bosnian Muslims are Jews, Serbs are Nazis" possible.
Since it seems that USHMM is into Holocaust diminishing business if it suits nefarious goals, perhaps they could pluck Ernst Zundel from German jail and hire him as a consultant. Perhaps David Irwing should apply for a job as well.
Another high-profile Holocaust diminisher, late Croatian President Tudjman, known for claim that only 900 000 Jews were murdered in The Holocaust has been already assigned an important role. He was present during the official opening of USHMM.
USHMM has done more damage to the memory of The Holocaust victims then Stormfront and other scum ever will.
Memory Eternal.