By many intellectuals and philosophers, like Karl Marx. How do you know you would disagree with their arguments if you didn't even realize such people exist? That's the "lack of understanding" I am talking about.

In fact, there are several different explanations why these are unethical. One (Marx's) comes from labor theory of value (which I don't believe in, I think it is self-contradictory, but even classical liberals did believe in, that's why they hated rent seeking).

Every ethical argument is based on some ethical principles (like axioms). The question is, do you disagree with the argument (the derivation of the conclusion) or with the principles?

I'm tired of this sophistry where people claim "this is not a real capitalism". Why cling to the term then? Capitalism has always been a designation of the actual, real system, not some liberal utopia with no rent seeking. (The actual reason is that you can, somehow hypocritically, acknowledge the flaws of the system, while claiming TINA, anyway.)

Knew it was going to be Marx.