Because they’ve idolized Russia for so long that to now admitt that they’re doing bad things is seen as a personal loss.

And some just genuinly believe the propaganda being fed to them. It’s very difficult to admit you were fooled and led to believe things that wasn’t true. It’s far easier to double down and confine yourself to an echo chamber where they can all agree that it’s somehow because NATO or US sponsored the Ukrainian uprising and rigged the Ukrainian election.

So when you think about it, they’re the good guys trying to restore order to Ukraine.