So what's your solution in such situations?
Not to kidnap males over 20-odd and send them to the front. Would you agree that this is never right, even if the other side does it? Nor to try and drag the rest of the world into war. Personally I think that the only justifiable response is sanctions.
If Ukraine had agreed to Russia's terms in March 2022, there would have been no murder, rape and torture, and Donbas would have been two independent states. Zapporozhia and Kherson would still be Ukrainian territory.
Yes, stopping the invasion would have been possible with NATO's modern air capabilities, but never rely on another nation for your own nation's security. That's what the West is doing with Ukraine, and we are now more at risk of nuclear war than we were before.