I see that Google, Facebook, Microsoft et al are conspicuous by their absence from that list. Kind of shouts out how little they feel for your (and my) data privacy.
I agree they were probably contacted, but still I'd like to know, in any case, what was the procedure behind selecting those (and not other) companies.
Bottom line - snooping is part and parcel of the business plan, they won't go against it, nor will they give it up.
But before jumping to conclusions, we'd have to be sure they were contacted for this? Maybe the authors of the letter assumed these companies wouldn't sign?
It would be telling if they refused to participate.
But you're right, I would've thought Google and the others would be the first to start a major lobbying campaign against NSA's surveillance powers. So maybe they don't really care about user privacy that much, or don't think this story will damage them too much in US or abroad, and that they don't really need to do anything to fix the broken trust relationship they have with their users now.