1) If you bought the game your opinion doesn't matter because Crytek have your money
(False because you influence other people)
2) You can't judge the game without playing it
Yes you can otherwise you'd have to buy games at random, obviously your opinion would not be as educated as somebody who had played the game. But in reality people make such judgements every time they buy or don't buy a game and lets face it we all played the demo.
Also it is interesting to note that in combination these two assertions literally invalidate every bodies opinion (edit: unless you pirated the game). Thats what I find most annoying about it.