Are you asserting that all economists and financial goobs are "BS artists," or merely most? Is there a way to tell the difference better than "he hasn't gone belly up yet"?
They're only asserting that some economists could get away with being "BS artists," so inevitably, some do. Obviously that hurts the study of economics as a whole, because if you can get away with BS, that means people can't tell what is and is not BS, so non-BS looks like BS and has to compete on points other than merit.
Certainly Taleb is referring to all economists, give or take a handful, not just some.
That doesn't matter. The point still stands so long as it is true for at least one economist.