(1) You don't see the problem with people who are better at manipulating and lying to others through deceptive advertising getting a bigger market share? That's just so obviously bad for society.

(2) Suppose you need insulin to live, but it's suddenly become a meme to start snorting insulin and all the stupids make the price shoot through the roof. That's what stupid people "making prices irrational" looks like, and it happens with fads, or inferior products, or even allowing actual scams to be posted in online marketplaces. Happy smiles on paid actors should not be enough to make your product more appealing than your competitors', and yet the stupids will drive out of business people who don't engage in such pathological behavior.