Your position is impossible to argue against in good faith when you start with "any Estonian who is critical of both of their occupiers is a holocaust denier".
I mean this with greatest respect: pointing out Double Holocaust Theory is not arguing in bad faith. It's arguing that there has been an organized push by antisemites to trivialize the Holocaust by equating it with crimes committed by the USSR. This mostly comes from 20th century anti-communist propaganda efforts. The forces that are trying to push the equivalency narrative are aligned with Nazi ideology or similar. Liberals may not care about the distinction because they figure that they can point at both communists and Nazis as being bad and move on, but doing so only assists the antisemites in their efforts. Point being, regardless of how you feel about the USSR or communism, you are effectively carrying water for Holocaust-deniers by failing to recognize the difference.
To be clear, I am not calling you an antisemite or a Holocaust denier, because it is very clear you are here in good faith trying to sort out this mess, and have been doing so respectfully. I am only trying to explain the argument so that you and others can attempt to make sense of the obvious dissonance between viewpoints. It's akin to unknowingly using ableist or misogynist language. If you're ignorant of the issue, then no one should ascribe malice to your language, but upon being made aware of the issue, it's expected that you should be more careful going forward.
Posting "[hammer and sickle] 10 reasons why we need communism..." is clearly not Kremlin propaganda. Posting "[hammer and sickle] Ukraine shouldn't even exist, long live CCCP" is clearly Kremlin propanda.
Again, with respect, I don't think this addresses the issue. I appreciate that you are open to the idea that advocating in favor of communism isn't de facto Russian propaganda (the current Russian state and ideological bent bears no resemblance to communism). Hexbear users are, at most, critically supportive of Russia for a variety of reasons that have nothing to do with Putin or Russian nationalism, and much more to do with criticism of NATO and the US, in particular.
I think what we're trying to figure out is how to engage when anything that doesn't explicitly agree with the Western narrative is immediately dismissed as Russian propaganda. As an example, the Snake Island incident last year smelled fishy, but to call the Ukrainian government's statements about it into question at the time would get one accused of being a Russian shill. We now know that the Ukrainian government lied about it. That's fair pool, as far as I'm concerned. It's how you wage an information war. I don't care if a state wants to lie about things (and states will do so regardless), but I do want to get as close to the truth as possible, and that means critical analysis and skepticism. If there's no room for that analysis and skepticism then it's effectively declaring not just an anti-Russian-propaganda position, but rather an active preference for Western propaganda over everything else. That, by the way, is a valid choice, but if that's the party line then it should be made explicit. It's valid to say "anything pro-Russia or anti-NATO is banned" but that needs to be said, rather than hinted at. "Kremlin propaganda" isn't a self-explanatory phrase.
All of that said, I empathize with you in your attempt to make sense of all of this. While there is a lot of friction here, I think most of us are earnest in trying to reach understanding, if not agreement. The above is an attempt to shed some light on what might be causing dissonance. You're very patient to try and work through this, and I hope I and my fellow hexbear users haven't caused you too much stress. Most of us really are trying to play ball.
In philosophy, it’s called Pasta’s Wager.