Greed is a disease more deadly than heroin, hardening your heart and turning you into a right-wing monster, driven to amassing ever more power and lucre until you feel absolutely justified in bending society itself to your warped, dystopian world view. Rockefeller, Walton, Koch, Ellison, Zuckerberg; all the same fuckers.
On the other hand, using "hate of greed" as a political weapon actually kills tens of millions of people, Mao (Great Leap Forward, Cultural Revolution) , Pol Pot (Killing Fields), Stalin (Holodomor).
As opposed to bringing you cheaper oil (Rockefeller), cheaper retail products (Walton), better mechanisms for oil refining (Koch), better databases (Ellison), and better ways to staying in contact with your friends for free if you are willing to watch some ads (Zuckerberg).
Moreover, it should be remembered that it is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest.