Like, I remember as recently as 2016, that term was just used as a mocking term for weird larpers. Now, it's used as a term for people they want to purge from the left (yes, I'm using those words. How they're acting is literally the definition of purging, it doesn't have to include violence).
Tankie = leftist
Leftist = liberal
That's the conservative lexicon, and liberals take their cues from right wingers, so they have adopted the former.
This has been the trend for years. Liberals get called "commie" "pinko" "Marxist America hater" by the GOP, so they start to think that those are just edgy synonyms for "progressive" (🤮🤮🤮). When someone who's actually a communist shows up, they freak out.
My job has me in other peoples houses, and one customer recently had their TV on something like Newsmax or some weird far right channel I'd never heard of, and the headline at one point was "Obama makes excuses for leftist failures."