I see it more of black and white, literally, writing in a contract. If I purchase an advertised product under a contract, the vendor usually must provide the product within a reasonable period of time, even if the time is not specified. The Federal Trade Commission and trade laws generally frown on selling snake oil to vulnerable people like myself. This is why such actions are prohibited.That IS a slippery slope, and soon religions will be banned too, for not delivering.
People need to have freedom to buy into stupid stuff, it's a basic human need, for some of us.