At least two reasons.
First, the ban for all Ukrainian men aged 18 to 60 to leave. That is just despicable.
Second, the apparent effort from Zhelinsky to drag all of Europe and the Western World into this. That is insane, for obvious reasons. If Ukrainians love their government so much that they want to fight the Russian invader, that is their prerogative, but we need to stay out of this. Ukraine is very much NOT part of NATO, so we have no obligation whatsoever to intervene, and that IMHO is a good thing.
There are other reasons but they are more subjective, such as our (I mean incels') contempt for Western governments and the suspicions that Zhelinsky is a puppet to them. Also the overall narrative Putin has laid out, about the West having played and made a fool out of Russia ever since the fall of the Soviet Union, using lies and deceptions to creepingly expend NATO eastwards, getting ever closer to the Russian border. I mean what kind of defensive strategy consists in expending towards the enemy?
It should be desirable for everyone that a tampon zone had persisted in Eastern Europe, and Ukraine was the last piece in that regard. Putin said he would not let it fall too, and I think his point of view is quite convincing, tbh.
View: https://youtu.be/APPjVlUA-gs
Finally, let's not kid ourselves, I think we incels have some sympathy for Putin, because we kind of see him as based. For instance, and as far as I can tell, he is one of the very few world leaders who publicly spoke against the woke nonsense. We tend to see him as a major obstacle to a clown world hegemony.