We have to be careful to distinguish between capitalism as an ideal, and as a description of what happens in the real world. (The same applies to socialism or any other -ism.)

Otherwise we will just engage in 'No True Scotsman' fallacies.

True, but fraud is not at all specific to capitalism in practice or theory.

I agree with that, but not everyone does. So at least being careful about _is_ and _ought_ (or practice and ideals) makes that discussion slightly less unproductive.

You'd probably agree that maximizing profit is a corner stone of capitalism. In practice this principle is way above staying within the bounds of morals or laws.

That seems like a fully generalised critique for almost all -isms.