Wikipedia article you are pointing at clearly says "The day has been controversial as the Legion is seen by some as Nazi and the Legion Day itself as a Nazi honouring, while others hold that the Legion was a purely military unit fighting against the Soviet Union that had occupied Latvia in 1940 and was not itself responsible for any of Nazi war crimes."

While you present that as clearly Nazi. That's not the case.

Still we can go even deeper in history and found some historic relations between Latvia and Germany.