Geocaching dot doesn't mark it as anything actually. It's the cache owners who placed the geocaches that chooses the country. GC5AVYA is marked as Russia for example.
Project-GC "chose" to make Crimea belong to Russia based on the same ruleset we have used for all disputed areas. One of the bigger factor behind the decision was that we looked at geocaches placed by local geocachers, in contrast to tourists. Note also that this decision was made well before the recent invasion of Ukraine.
We try to stay out of politics as much as possible, but it's clear to us that it's impossible. There has been many decisions taken the last 10 years that has met criticism, and would have met it if we took another path as well. Crimea is far from the only disputed area in our world, sadly.
Most of the geocaches marked Russia has recently been archived. To our understanding due to geocachers harassing the cache owner(s).
When the war has ended Project-GC will reevaluate the area, but not before then. It's also likely that even when the actual fighting and killing ends, it will take years before that area is stabilized again.