I think a lot of people are supporting this because they misinterpret the demand from the way it is written.
(Or maybe I am, and it’s written correctly, but I don’t think that’s the case.)
My understanding is they have to allow the iPhone to interoperate with 3rd party devices - NOT that they have to offload their software ONTO third party devices.
So it’s not sharing IP. It’s still very much closed-source and belonging to Apple. But they can not just… block out your google watch, or your Samsung headphones, for instance.
If my interpretation is correct, this is a big, big win for consumers.