I think I am understanding you very well. You say democratic imperialism is just as bad as autocratic imperialism, creating a false balance when you agree that autocracies are inherently worse for humanity than democracies. Furthermore, Ukraine was attacked by a far more capable force than their own. They, by the very definition of imperialism, cannot be imperialistic by simply fighting for its own survival against an autocratic and clearly imperialist Russia.
Your first paragraph ist simply paraphrasing my entire comment, so you agree with me. Regarding your second paragraph: Then why did they attack and invade Ukraine, if it is neither a threat nor a rivaling power? Kind of looks like Ukraine having not enough arms to defend itself was one of the prime motives for Russia.