i do not think it is a question of logic or morals, it is a legal question. it is the law, like it or not. break the law and you risk the consequences.
you can tell a cop you did not know the speed limit, or it does not matter cause no one was hurt, or a million other excuses. chances are you still will get a ticket.
KNOWS the beans aren't magic and tries to claim they are to prey on the stupidity and/or gullibility of the buyer, then yes he should be able to sue and the government should prosecute.
You aren't allowed to sell knowingly defective products. neither should you be allowed to knowingly sell phony stock or magic beans