If we are discussing morality and philosophy, I would argue that the question is still not “murky”. I reject your premise that a one cannot make arguments as to the morality of future actions, for a person who has committed immoral acts. If we can accept the premise that Russia’s war in Ukraine is that of an aggressor state, participating in it as combatant, is immoral. Going to jail for refusing to participate in it, is not immoral. Whether or not that person has previously ground up people, is not relevant.
That doesn’t mean the decision is an easy one to make. Or, it’s much less easy than it is for me to armchair my words around. But I don’t think morality is hard to pin down here.