For me the "defending it" is the line. So long as the person is honest in doing it just to pay their bills, that's good enough. And it's obviously better if they're an actual comrade and do praxis some other way in their life.
I've also ended a friendship over a friend trying their damnedest to portray the landlord and hedge fund corporation she worked at as "progressive actually". I think there's this tendency to force oneself to believe one's work is always a net positive for the world somehow.
This is a bad post and all, but take this moment to both consider what "critical support" means and in which contexts you should use it.
It depends on your broader strategical goals. If you are a Venezuelan or Haitian communist/socdem for example, critical support for Russia means taking some pressure off of your back while gaining a potential ally. If you support Chinese Socialism, the war also depletes NATO before it can go against China.
If there were conditions for a revolution in Ukraine when the war broke out, it might make sense for those revolutionaries to align with either or neither army tactically for the broader strategical goal.
Morals are secondary, as they define your strategy, not your tactics.