This obviously curtails free speech
As an aside, in a strict, Constitutional kind of way, the idea of guaranteeing free speech is aimed at governments, not at private parties. The EULA is, at least in its designers' minds, a contract between parties, and it's hardly unheard of for contracts to include provisions for what can and can't be said about something -- that's what an NDA is, for example. I'm not sure that the idea of "free speech," as commonly understood, is even applicable in civil law, or perhaps in contract law. (I'm no lawyer.)
I mention this only because people occasionally get confused about constitutional rights, which, as noted, are designed to curb the US government, and people occasionally think that rights like "free speech" et al are absolute rights that always apply in all circumstances. Not so. Else such a contract would be unconstitutional, which it is not.
Ok, back to EULAs.