Bad things are being done, by a small minority of the world’s richest people. The wild parts of the theory come from individuals who need an excuse for their personal failures.
Evil people use minions who need an excuse for their personal failures. The Evil ones then encourage the minions to envy and to commit theft from specified targets. And to do worse things. The minions do them voluntarily. The masters sit back laughing and never get their hands dirty.
Evil scales at every economic level. It is not the "billionaire class" that is the source of this problem. But the sociopaths among them have more minions and can do more damage.
Hitler, Stalin, and Mao never killed anybody. Their public servants did the killing.