Except they’re not celebrating Nazi collaboration. They’re recognizing people who fought and died for Ukrainian independence. However tainted that struggle is by the people they fought for and with, and even sometimes the actions of those armies, it’s not them celebrating or recognizing Nazi collaboration. It’s a recognition of the fight for independence.
To me, this is like recognizing Thomas Jefferson’s contributions to the founding of the US. Is someone who makes that recognition endorsing slavery and rape? No, they’re not. Because he’s a more complicated historical figure than just a random slaver and rapist, and it’s hard to tell the story of the foundation of the US without talking about his positive contributions.