I'm mildly surprised to do a quick search on this HN thread and not see the word "adhesion" appear. These microcode patches are for a significant design defect in a product that Intel already sold under both explicit and implicit promises and expectations of general functionality. The microcode patches aren't some luxury fully optional deal to make pretty patterns with case LEDs or something, they're a matter of critical safety and
failing to install them might even expose downstream users to liability issues were the security problems to ever subsequently be exploited and then cause damage to a 3rd party (or even themselves, cybersecurity insurance is still a pretty new area but one of the few policies I've see had print I understood to be along the lines of "insured is expected to take reasonable precautions staying up to date with known patches"). Furthermore, Intel obviously presents no other options for users, using cryptographic signing to ensure that (even ignoring practical issues) there are zero other options to get microcode from.
At least from my layman's perspective this certainly smells like an absolutely 100% textbook contract of adhesion. It's a "take it or leave it" offer, there is no room for bargaining, the term is far outside of reasonable expectations for the situation, it's simply an entirely one-sided item for the pure benefit of Intel leveraged coercively. In fact I think it may go far enough to hit the doctrine of unconscionability even. All this without even touching on any public interest issues.
I think they should be challenged on this, that benchmarks should be published and Intel told to pound sand. Companies can stick whatever they want in a contract but that doesn't make it enforceable. And while admittedly often that can be quite gray territory and people toss out "not enforceable!!!" on the Internet far, far more often then is justified this particular instance really does look egregious. Yes, normally you can contract away your speech rights, but it's in the process of a real contract, with reasonably equal bargaining positions, proper consideration, etc. I think this goes too far.
Perhaps Intel's real aim though is actually slimier, lots of major review sites depend pretty heavily on access that Intel (and other vendors) offer as well as free/cheap kit and the like which is optional and much easier to yank away at a whim. For those publications this may be a shot across the bow, of the sort "sure, you can challenge this if you want but it's a warning that if you do we can still punish you for it regardless of you winning the case."