I would argue a dealer telling you about a major defect directly before you buy the car is a bit different than a post on some forums that the product they're selling is not well made.
I would suggest it's not reasonable to expect that someone buying a game has to do research on a forum to know the game is unfinished -- if it's being sold as a finished game it's reasonable to expect it's in a playable state. the original post was meaning to say it would be unheard of for other products to allow companies to sell known unfinished products as finished products, even with the promise of completing the product. and consumers would similarly balk at such a proposal for virtually any other object.
it was more the absurdity of the different way games are treated which is anti-consumer.