My phone is my phone, not Google’s. They have absolutely no right to prevent me from running whatever software I wish on that phone.
This must not be allowed to stand.
Smart phones try to limit and firewall the interface between the two but tight integration is required for energy efficiency. So a smart phone, or a cell phone, can never be yours. They aren't good choices for doing computing and this legal reality is becoming more and more obvious with time.
Maybe people live in a country where adding new regulations is difficult at the moment. In that case, push at for it at the state or province level. Push for it wherever you can. Suddenly these companies have to figure out how to work around 50 different state level laws? Painful. Good. Make it hurt to be evil.
People need to come together and push for regulatory roadblocks to things like this at every level. I think that's part of how you keep control of your own property and stand up against it.
You didn't fund the development of the OS, contribute to it (presumably), you didn't market it or position it alongside your brand.
I'd agree with you if you said you have a right to run anything on the hardware under a different OS, but you have no god given right to run whatever you want on the OS.