1. There's no reason to think the criminal invasion of Ukraine will result in victory for Ukraine. The Russians will fall short of their maximal goals, but they're having significant battlefield successes now. Sometimes, criminal invasions are completely successful. In this case, I suspect that a long, low-intensity conflict with two entrenched sides is the most likely outcome.
2. This is not the greatest atrocity of our generation. There have been at least three invasions and occupations that are significantly worse crimes: the US invasions of Iraq and Afghanistan, and the Saudi-led invasion of Yemen. All three have led to the total destruction and failure of the invaded state. Ukraine has lost territory and there has been substantial suffering, but it has not been nearly on the same scale and the social disruption has not, at least yet, been anywhere near as significant.
I bring this up because moral consistency is important. Just as we should endorse the right of the Ukrainians to defend themselves from criminal aggression, we must also endorse the same rights for other peoples. And we should be making the same calls, or not, for the aggressor states in these crimes to have their cultural influences purged from law-abiding societies.