"But let us never forget, either, as all conventional history of philosophy conspires to make us forget, what the 'great thinkers' really are: proper objects, indeed, of pity, but even more, of horror."
David Stove's "What Is Wrong With Our Thoughts" is a critique of philosophy that I can only call epic.
The astute reader will of course find themselves objecting to Stove's notion that we should be catologuing every possible way to do philosophy wrong. It's not like there's some originally pure mode of thought, being tainted by only a small library of poisons. It's just that there are exponentially more possible crazy thoughts than sane thoughts, c.f. entropy.
But Stove's list of 39 different classic crazinesses applied to the number three is absolute pure epic gold. (Scroll down about halfway through if you want to jump there directly.)
I especially like #8: "There is an integer between two and four, but it is not three, and its true name and nature are not to be revealed."
I define gibberish as "difficult to understand and entirely or almost entirely meaningless". I think Plotinus and Foucault are "difficult to understand and entirely or almost entirely false". A statement is meaningless if it either fails to follow rules of syntax, i.e. "Running the the snacks on quickly!" or semantics, i.e. "Green ideas sleep furiously."
The distinction is actually pretty important. If you know something is meaningless then you can move on, but you can't decide something is false without first considering the argument, obfuscated or not.
There is some middle ground when it comes to arguments about things that don't exist. The trinity argument (and probably Plotinus) appeals to something that doesn't exist and so it says things that would be meaningful if the holy trinity was real but can't really be evaluated since there is no such thing. Obviously there is no reason for you to care much about this argument. But I don't think Hegel, Foucault or Heidegger and the other usual suspects are talking about things that don't exist.
Syntax does rules necessarily broken imply meaninglessness not.