It is tough choices, I agree. I usually block only communities and users, but I have blocked some instances, that pop out as constantly bringing annoying posts on my feed. Personally I have very low tolerance for tankie propaganda, but on the other hand I also hate the Usaian discourse dominating everything, and try to block the communities having only USA-centric news and political debates. I guess we all just have to choose, for what reasons we interact with platforms, like these. I do it for fun, and that means I am “trigger-happy” when blocking - you might be seeking something else.
But yes, that I think arguing with tankies and the like, ends up being practically pointless, or even harmful. A lot of them seem to be just "Winnie the Pooh"s propagandists, so they are not interacting in good faith. They will just gishgallop with walls of texts, to exhaust you, and interacting with them just allows them to get more visibility, and spread their propaganda even further. The same applies to other propagandists too, but on Lemmy I have mostly seen just “tankies” doing it for China and Russia.
Sadly this also means, that if they post heavily on some instances, that could have some good purposes (like the anarchist ones), in the end interacting with those just gives them more visibility as well. You can also easily spot, when you hit the nail in the head and found them, when you criticize Russia or China, and get a lot of downvotes. I know many people think, it is good to see the opposite opinions, and I agree. But when there is so much bad faith actors around, in the end, it is going to affect you negatively, in one way or another.
Edit to add after I saw the last line of your comment (did you add it late? does Lemmy support ninja-edits like Reddit?):
I did not add it, but Lemmy allows “ninja-edits” for few minutes after posting, I think. I personally aim to mark, when I edit the comments, so people do not have to guess what changed.
Yes… at what point do you stop blocking the single posters, but block the community instead? And at what point do you stop blocking the communities, and block the whole instance? We all draw those lines differently, but it is definitely not easy, when you also want to interact with the people thinking differently, but also in good faith. And how to spot those people, from the mass of bots, propagandists, trolls, and useful idiots… And not end up wasting that time, or unintentionally boosting their message.
Though, for me the last line absolutely is drawn in the genocide-denialism, as for example defending Chinas “assimilation”, is just wording genocide to sound palatable. If the moderators of a community accept it, and other users upvote it, it goes into the “sitting at the table with nazis”-metaphora, for me. It really is very important, to hear other viewpoints, to avoid the echo chamber, but I also refuse to become a part of the crowd even just accepting the approval or defending of attrocities from the sidelines. Some people of course do find something worthwhile in reading, or even taking opposing part in even the worst discussions as well, but I just get unhinged and extremely angry, and that is not a good thing to expose yourself to all the time. Especially, when I seek the mentioned fun here, be it memes, or meaningful discussions (like this one), as I already get my dose of Awful, from following the news from multiple sources.