I think these companies are acting on pretty high principle.
NOt that i disagree, but I do think if other companies (eg, apple, intel) signed off on this it would remove the stigma of self-dealing. If the "tech industry" was more broadly represented (and included say, Stanford & MIT) again this would be a much more powerful statement. But the reality, is that SV lives off of the governmnet in many indirect ways (nasa, defense, NSF grants, etc) and while they may be principled...well, I sure you get the idea. They're not that principled.