It is honestly pretty simple:
US = bad -> anti US = good
Add to that the idea that revolutions are inherently violent and killing of some traitors is fine and you have your tankie. For dictators being somewhat anti American is a pretty good strategy. The US propaganda is pro democracy and that is a great enemy for a dictator, the US also does a lot of evil shit and the fact that your country is poor is all to blame on the US and absolutely not on the dictators stealing everything. That btw is also why “socialism” never worked for tankies. As in it would have been perfect, but the US destroyed it.
As for many of the best stories, there is a good bit of truth in it. As in the US actually does a lot of evil shit and 100% fights leftist movements. However it is not always the bad guy and two bad guys can fight each other and do so all the time.
No worries the FF(X) cutters will come soon to relieve the destroyers.