The non-racist lesson they could have taken from the Holocaust is: “Never again shall be this be done to anybody”
Instead the German elites (who, remember, were brought up in the very same time and environment as the NAZIs, with for certain many who quietly sympathized with some NAZI views) very openly chose for their country to learn a different lesson, one that preserves the Racist view of Human Beings: “Never again shall Germans do this to Jews”
This “lesson” in Racist format then anchors the utterly immoral and anti-Humanist idea that for Germans a Genocide is unimportant if not done by actual Germans and if done by people claiming to represent Jews, then Germany has a moral obligation to support them.
The Humanist version of the lesson, on the other hand, is wholly incompatible with closing one’s eyes to Genocide, much less to supporting those committing Genocide, no matter what the ethnicity of the mass murderers or their victims.