Maybe because neither economics, nor manufacturing nor any other field, are fields to be left to the "experts", to the exclusion of the citizenry in general (economics especially, as a soft science that leaches on Math and thrives on state power, is full of idiotic experts, with Phds and Nobels to match, whose aggregate predictive performance is closer to a coin toss, if not negative).

Not to mention that arguments are to be judged in themselves, not based on the expertise of who's making them.