He most likely doesn't believe Ukraine is able to maintain their territory protected from Russia with NATO's weapon supply, and for good reason, given how clearly this is demonstrated by the utter failure of the vaunted counter-offensive. The only thing your position is really advocating is the useless deaths of vast numbers of Ukrainians (and Russians, for that matter).

No, just as it would be unable to resist NATO in being turned into a far-right paramilitary-led banana republic if Russia were to suddenly withdraw without any decrease in NATO involvement.

But the beauty of the neat little trick above is that if the working classes of both sides correctly oppose their respective ruling classes' interests, we can end up with a scenario where both sides lose - objectively the best outcome for the Ukrainian people, as well as everyone else.

The Russian anti-war activists are clearly holding up their end of the bargain. Why are you not holding up yours?

It can involve that. But you're using imperialism to "accuse them of what you're doing before they can" by flattening all history and context away.

Russia is defending itself from encirclement. Acting like you're against imperialism rings hollow when you only apply it to an act of resistance to your empire expanding.