Remembering to look for and ignore folks with that telltale indicator has made the fediverse so much more enjoyable.
The original term "tankie" refers to the usage of tanks way earlier, by the USSR in the Czechoslovak revolution attempt.
China did not use tanks against civilians in the Tiananmen protests, the famous picture of "tank man" is a screenshot of a video in which the civilian stops the tank, has a ten minute conversation with the tank driver, and then goes away by himself.