A tankie is someone who defends Chinese and Soviet communism and denies that any of the claimed atrocities happen. In the name of Marxism-Leninism, or Maoism, or Stalinism, they get very angry, attack you and ban you if you think differently, and will fight to the teeth to claim that the tiananmen square massacre, the uyghur genocide, holodomor, any other genocides by Mao, Stalin or whoever you want who's communist, are Western imperialistic propaganda. And that's just the tip of the iceberg. There's a whole thing there just like nazis aren't just "people who hate jews but claim the Jewish genocide never happened". Tankies usually also defend Russia in the Russo-Ukrainian War (or "conflict" as they may claim). Then again, Trump supporters usually also defend Russia. Maybe the horseshoe theory is not that crazy.