anti-authoritarian leftists, including anarchists, libertarian socialists, left communists, democratic socialists, and reformists(who commonly use “tankie”

Ah yes, the anti authoritarian anarchists like the Ukrainian Free State, a military dictatorship that enabled pogroms against Jewish people in their territories.

The marxist leninists were in practice a lot more anti-authoritian" than the anarchists and other "anti-authoritians" of the time.

USSR was justified in using tanks to crush a revolution

noted anti-stalinist Khrushchev sent tanks into Hungary
I would also send tanks into Hungary -even if we were close to a peaceful settlement- if I suddenly got reports of soviet government officials and jews being lynched. Revolutions don't start lynching jews. Counter-revolutions do.

This happened a decade after the holocaust in a country that the Soviets failed at denazifying as successfully as other Warsaw pact countries. Hungary was an enthusiastic collaborator in the holocaust. You do the math. The vanguard of the true revolution they were not.