The reason why there are so people attacking ANY game (not Portal exclusively) for day 1 DLC and various pre-order bonuses is because this sets an example. If people are willing to buy only complete products, then companies would not try to pull this kind of stuff. If users show that they are willing to shell out cash you get things like Capcom and EA where complete DLC is sitting on the disk waiting to be unlocked.
Here is a short, and quick, list of things you skip and still finish a game (not talking about Portal 2 atm):
-Side quest
-Side characters
-Minor characters
-Most of the major cast
-Anything besides the basic story outline (There is a bad guy, stop him. Motivation and so forth aren't necessary for finishing the game.)
-More than one weapon
-Alternative routes (even in level design, left path is 0.99$)
-Main character voice (everyone could be Gordon Freeman)
-Co-Op
Just to name a few. Can we live without those things? Yes. Should we?
I don't think anyone is against Portal 2, but things like that signal publishers that people are willing to gobble it up. EA is getting flak for it, so is Activision and Valve is no special for it. People don't want gaming to turn into that kind of a beast.
Just to clarify, I haven't taken any actions against Portal 2, hell, I don't even care about the game, but I can fully understand why some people do it.
Unprofessional and uncool Shamus, calling people idiots for not agreeing with you is pretty much what your accusing them of
Also - this. I've seen blogs more professionally written than this.