It is quite possible to be smart and wrong.
I changed my mind about reading Marx, because even if he's wrong on most things, Das Kapital still challenges you to figure out WHY he's wrong. He has a logical progression that you can follow to find out the conclusions he comes to.
Noam Chomsky's "Manufacturing Consent" is a pretty good book.
The Communist Party of the USA in the early-to-mid 20th Century had smart ideas about how to subvert the country into communism.
But modern leftists aren't worth a single shite. The leftist politicians are complete retards (like AOC) and Breadtube is filled with perpetually pearl-clutching moralizing fags whose brains would be better used as wall decoration.
Modern leftists are not only wrong, they're stupid, dishonest, and wrong.