And I understand that western countries are reluctant to impose a no-fly zone out of fear that Putin has gone insane and might resort to nuclear escalation, but I think the risk of him resorting to nuclear escalation already exists if he can't have his way with Ukraine. And there are a lot of Russians who strongly disagree with this war and would probably support a no-fly zone.
I fully admit that if Putin has indeed gone nuts and isn't merely playing games, then we have to trust the Russian military in control of the missiles to do the right thing, but I think that trust is also warranted; many Russian soldiers already don't want to fight, and I'm sure the more competent commanders are well aware that a nuclear attack would be suicide.
No, the fear is that Putin is basically sane and operating under something like normal great power expectations despite his crimes of aggression, and thus will not attack NATO countries for fear or nuclear retaliation, but will escalate against NATO countries if they intervene directly against him, potentially and quickly leading to nuclear war.
If they thought Putin was insane, the marginal risk between aiding Ukraine and intervening directly would be less, not more.
He is claiming that the Neo-Nazi units of the Ukrainian military operating in the south of the country, who harbor Nazi tattoos and whose flags represent the Black Sun and the rune used as the symbol of the "Das Reich" SS division, are probably Nazis. The Australian terrorist Brenton Tarrant mentioned, in his manifesto, that he had visited those guys.
Last year a UN resolution was motioned to condemn Nazism and Neo-Nazism. Only two countries voted against: the United States and Ukraine.
This doesn't justify any war of aggression, of course, but you cannot pretend that there is no Nazi problem in Ukraine either.
Of course he is not claiming that the Jews in the government in Kiev are Nazis, because that would be absurd, but it's pretty clear that they are tolerating Nazis in the military for very cynical reasons (they're actually very effective fighters and are employed to fight the separatists in the Donbass region).
Are you sure about that, to the point of risking the continuity of the species and all of our modern civilizations upon that? If one can claim that the Jewish population in Ukraine is actually Nazis and have many of their citizens believe it even as the economy is collapsing, i doubt that justifying even greater crimes against humanity or other horrible actions is out of the question.
It breaks my heart to see that bullies like Putin are allowed to largely get away with what's going on (apart from support for Ukraine by the international community, though that's essentially funding a proxy war and civilians and the culture at large will still suffer immensely), but you also have to understand the reluctance of other countries to escalate.
And to prevent anyone dismissing the above arguments due to my biases towards the western perspective, i've seen people on /r/russia attempt to justify their military's actions by recalling past actions of western regimes. Just to be clear, i condemn all actions like this, regardless by whom they're perpetuated: two wrongs don't make a right. Humanity should learn to talk, though i fear that there are irreconcilable differences as well.