I'm typing from my phone, but I'll try to answer all your questions...
Who decides what features are optional? Well that's an easy one, the game developer does! They set all the menu options, and sometimes settings can be changed via ini files and the like.
That also answers the next set of questions, oddly enough you didn't list the devs as a choice...
AMD can disable anything they want when their chipsets are used, but good luck selling many CPUs when this happens... They are in no position to do such a thing, so arguing that point is, well, pointless.
As for your last question, I don't speak on other's behalf, nor do I have any way to know how they would react. It's a silly question, to be honest.