But it is for security reasons - it is always about security reasons when old devices and now even old apps have to be thrown away.
I would argue that because this is a new OS and not an update to an existing one, “right to use” doesn’t really apply. Just don’t install the new OS.
OSs make decisions about what we can run all the time, intentionally or not. But as long as you aren’t prevented from using what you already have, I don’t really see it as a “right to use” issue.
You have the obligation to use it since the manufactures doesn’t gives updates to various versions of the OS, for example, if the device has version 13 and there is an update for 14 if you choose to not get the newer version you’ll not get security updates for version 13. Also, newest devices will get only version 14 (or newer) and with the boot loader locked you can’t install a different version of the OS.