You're absolutely right that there is an enormous difference in the policies implemented by the various governments, I'm just saying that the policies were partially driven by a common psychology.
Pathologizing your political opponents is a two way street[0]. Your opponent might be insane, yes, but it can also be all too easily deployed to dismiss your political opponents and a lost opportunity to learn something, if not in the substance of what they're claiming, then at least about the causes. Even assuming that the various conspiracy theories peddled by both the Left and the Right are bogus (and they are), the fact remains that their exists widespread, politically useful grievance that makes them attractive to many people. If you just say "oh, they're all just mentally ill", you haven't learned anything, even if the grievance is simply a manifestation of envy and ressentiment. Even if they are all mentally ill, you haven't learned why they're all insane. Maybe you don't care, and that's fine, but someone has to care because unlike the occasional neighborhood eccentric, these things are political gunpowder. So first we debate, and only later do we embark on something like psychoanalysis.
W.r.t. Putin, I think that flippantly accusing him of mental illness is lazy and shows a lack of political imagination. That's only a conclusion you reach after you've exhausted all other options. Historically, Americans have been notoriously bad at understanding Russian political motives and the Russian political mind. If you contextualize what's happening in the geopolitical context, it's unclear, at least to me, that what Putin is doing is through-and-through insane. All evil is insane in the final analysis, but in the immediate sense, there may be a method to the madness. If you don't know the aim, and you don't know the constraints, you can't really understand the means. I'm not interested in cocktail party conjecturing or the pretense of knowledge.
For what it's worth, I generally agree with what you're saying here (and I vouched for your comment, because I thought it was an insightful contribution to the discussion).
I should clarify, though, that the "psychology" I am talking about applies more to the supporters of these political movements than to the politicians who lead them. It's completely possible for an intelligent manipulator to spout some narrative that appeals to the public's psychology, without them believing it themselves.
Your point still stands, though, that it's not enough to simply say "the leader is a liar, and their supporters are mad", because that reductionist framing is more likely to shut down any attempts at further understanding than to open the door to learning that there might be legitimate grievances that are leading to this "madness".
As for Putin, I think he is dangerously sane, but that's not to say that a psychoanalysis wouldn't reveal a helpful understanding of his motivations and weaknesses. For example, it seems that he spent his early life believing in (and working for) the greatness of his country which was destined to conquer the world (as if it were a game of chess played out across a world map), only to watch helplessly as that was all ripped away from him by the West. That could be psychologically devastating and create a trauma that has stayed with him for his whole life. I could well imagine that from his perspective, if he doesn't take back control of Ukraine, his whole life has been for nothing.
