I think that most acts of repudiation of the Holocaust and the actions of the Nazis were anchored in the mindset of the 40s and 50s, which was deeply Racist, hence why they’re all about the victims of a specific race (conveninently ignoring that the Roma people as well as those who had disabilities were targetted just as hard by the Nazis).

This stuff basically calcified a certain view of the World, even whilst the World kept on evolving away from viewing people first and foremost as “ethnics”.

This would explain things like Germany politicians supporting yet another Genocide along racial lines and justifying that support by the race of the genociders, the support of Israel by the very same countries which supported the white colonialism in Appartheid South Africa and Holocaust rememberances completelly ignoring the victimization of people who are not seen as part of a “white non-christian” ethnicity.

The modern learning of the lessons of the Holocaust would’ve been “Never again shall this be done to anybody”, but the 1940s/50s learning which is the one which clearly (in light of the actions of Israel and the support for it in many countries) ended up encoded in most Rememberances and is still interiorized by many was instead the Racist version: “Never again shall this be done to the Jewish People”