I'm not saying you're right or wrong, but here's a question for you. Suppose the Indian nations in, say, Maine claim that they have been treated unfairly by the federal government. And they have ample evidence to prove it.
So by a large margin, the nations decide to break away. It's all about freedom, the freedom of the nations to decide their own future.
Would Russia be doing the right thing by supplying arms to the nations? And how would that affect the stability of the world?
No - you're saying I'm wrong. And your argument is a reasonable one. Here's the difficulty - your analogy could be applied to the former Warsaw Pact nations or, indeed, to any nation in the world that has been been overrun. Should we de-recognize governments of the nations of the former Warsaw Pact and demand that they surrender their sovereignty to the Russian empire? After all, Russia did conquer them fair and square during WWII, at the cost of millions of Russian servicemen. Wouldn't Eastern Europe be much more stable under Russian tutelage? Doesn't the Right of Conquest mean anything, any more?
Notwithstanding the reductio ad absurdum I posited earlier, note that Ukraine is a sovereign nation. It is not a part of Russia. A more appropriate analogy would be whether anyone should object if we invaded and annexed Cuba.