It means exactly the same thing that “commie” meant during the cold war, it’s just an updated version to for people who don’t want to sound like red scare era boomers.

Directly from Wikipedia:

The term “tankie” was originally used by dissident Marxist–Leninists to describe members of the Communist Party of Great Britain (CPGB) who followed the party line of the Communist Party of the Soviet Union (CPSU). Specifically, it was used to distinguish party members who spoke out in defence of the Soviet use of tanks to suppress the Hungarian Revolution of 1956 and the 1968 Prague Spring, or who more broadly adhered to pro-Soviet positions.[6][7] The term has extended to describe people who endorse, defend, or deny the actions of communist leaders such as Vladimir Lenin, Joseph Stalin, and Mao Zedong. In recent times, the term has been used across the political spectrum and in a geopolitical context to describe those who have a bias in favour of anti-Western states, authoritarian states, or states with a socialist legacy, such as Belarus, Cuba, China,[8][9] Nicaragua, North Korea, Russia, and Venezuela.

So OP is basically saying they love it when governments crack the will of their people by force as long as its their team doing it.