There are two fundamental versions of the Holocaust, one that was created for war-propaganda, which is not primarily about Jews, and a very different version that was created for Zionist propaganda, which is all about Jews.
The Trump Administration issued a statement on International Holocaust Remembrance Day that did not mention any particular ethnic group as the victims of the Holocaust. Representatives of Jewish organizations immediately demanded that the presumed oversight be corrected, but the Trump Administration refused to do this, stating that they did not wish to commemorate Jewish deaths to the exclusion of the many non-Jewish deaths in the Holocaust.
Deborah Lipstadt and others stated that the Holocaust was by definition about Jews exclusively, because that is how they define it. Yehuda Bauer of Israel’s Yad Vashem Holocaust Museum even repudiated the proposition that there were several million non-Jewish deaths in German concentration-camps, pinning the blame for the legend of the “5 million” on Simon Wiesenthal.
In fact the claim of millions of non-Jewish victims dates from the war itself. In early propaganda about concentration-camps, Jews sometimes were not mentioned at all. What has happened is that the original story of German atrocities, which emphasized a diversity of victims in order to convince non-Jews that the war was necessary, has gradually been overshadowed by Zionist propaganda that essentially has no use for non-Jewish victimhood.
The conflict between Trump and the Defenders of the Holocaust Faith is based on the fact that Trump has adhered to something more or less resembling the original war-propaganda (which continues to exert influence because it was never authoritatively repudiated) instead of embracing the currently prevalent Zionist propaganda. By attacking Trump over this, they have called attention to an enormous change in the Holocaust narrative, which provides obvious justification for questioning other elements of the story.