As for the people I don’t know Salvador Allende nor Jacobo Arbenz, but Fidel and Che were two bloodthirsty armsmen that just picked up whatever ideology fitted at the time. There is a reason why since then until now people try to escape from Cuba into the US. Also, I believe the US only really took an interest in them when they accepted the Soviet nukes.
As for Martin Luther King Jr, he was definitly persecuted, but was it because he was a communist? I’m not sure of that.
Do you really want to use the Korean war as an example of the US oppressing communists? Really? You literaly just have to compare how both sides ended up.