Tankies don’t usually believe that Stalin or Mao “did nothing wrong,” although many do use that phrase for effect (this is the internet, remember). We believe that Stalin and Mao were committed socialists who, despite their mistakes, did much more for humanity than most of the…
saying that phrase is legitimately intended to be trolling- it's not meant to be convincing to the recipient or "activism". at some point you start to care less and less what reactionaries think. It's nigh impossible to convince anyone with arguments on the internet anyway.