People can be dirtbags with or without money, but having big money does two things:

Gives you the tools to wreak far more damage than an equally toxic poor person could do, and

Heavily reinforces the rich psychopath's narcissistic feeling that HE or SHE is special, better than and apart from the Little People -- which in turn makes it easier (and at the extremes even "necessary") to eliminate those lower-caste humans.