"Tankie" doesn't really mean much in practice. Many of us are communists who think that places like the ussr, n korea, cuba, vietnam, and china aren't unremittingly evil, and we have exhaustive sources to back it up. We also know the history of events like the 1932 Soviet famine aka the "Holodomor", the June 4th incident aka " Tianamen Square Massacre" and a bunch of other anti-communist shibboleths. A whole lot of people who think they're leftists but aren't completely uncritically accept anti-communist propaganda with no awareness whatsoever that it's propaganda. And they hate being told that it's propaganda, that it doesn't relfect what happened and deliberately distorts history, often to the benefit of warmongers and fascists. So they call us tankies to indicate that we're evil genocide deniers and you shouldn't engage with us because we might start showing you well documented historical sources that contradict the propaganda and then you might become a genocide denier too! It's all very silly but most Americans and many Europeans think they're immune to propaganda and whatever the news and government says it 100% true.

"Authoritarians" is also mostly an empty accusation. There's no realy consistency about how it's used. People claim any government they don't like is "authoritarian" but generally can't explain how the features of the government they don't like differ from the governments they do like. They also often have very naive or just flat out wrong ideas about how governments they like work.

We're not trying to antagonize other instances specifically. We hate liberals and liberalism for making the world in to it's current miserable state, and there happen to be a lot of liberals in the lemmyverse. We also post far, far, far more than almost any other online community. No one needs to tell us to brigade an instance, we all decided to get stuck in and start arguing on our own, no coordination needed.