You both make some valid points. Many honorable men served in the Waffen SS. And the Latvian SS members were, by and large, anti-Soviet and not pro-Nazi.
But there are some organizations that are so odious that the amount of evil in them overwhelms anything good that you can say about them. The Waffen SS was one such organization.
If some Latvians want to hold a general ‘Day of the Defenders of Latvia’, okay. But to specifically honor units of the Waffen SS is vile. It would be like honoring an abortion clinic because it once actually saved some woman’s life.
I think you are confusing the Einsatzgruppen with the entire Waffen SS. The Waffen SS had about 6-7 division, including regular Infantry and Calvary divisions among them. They were many Waffen SS units who fought honorably and bravely.
As to the Latvians it seems that they were forced into this and they don't have any other group to celebrate.
The day was "Remembrance Day of the Latvian Legionnaires " - meaning specifically Latvian soldiers who fought for Latvia against the Soviets. it is not to honour the SS.
“But to specifically honor units of the Waffen SS is vile.”
Non-Germans were not allowed to enlist in the regular Wehrmacht. The Waffen-SS was the only choice they had.
The 40 Waffen-SS divisions raised during WWII included Latvian, Estonian, Finnish, French, Belgian, Hungarian, Albanian, Croatian and Dutch divisions and various sub-units.