No, they're not. Few, if any, immigrants are. Indeed, if one looks at the statistics some of the most dependent populations in the US are rural ones that have been here for generations. The US also has a history of treating Haitian immigrants much more harshly than those from Cuba, possibly on racial grounds.
There do seem to be, however, large numbers of people who believe maltreatment of people is limited to a particular group or ideology, whether it be political or religious; I'm not including you in this group. Most of the communist regimes came to power because they overthrew some form of absolutist regime, like Battista or the czar (yes, I know the czar had abdicated before the bolsheviks took over, but his successor's hold on power was still tenuous. He was also naive, in arming the bolsheviks out of fear of an encroaching pro-czar force which turned out to be illusory), not because they replaced a democratic system.
As an aside, when I was in college, our assigned readings included Lenin. Read him and you will find one of the most cynical, self-aggrandizing, power-obsessed human beings to ever inhale. No wonder the Germans chose him to be the ultimate weapon to get Russia out of the war.