Is this a GPL violation?

the disagreement and argument comes in over the definition of 'use'

you can use the source code in anything you want to write, that's not the same thing as saying that you can run any software you want to write on that particular piece of hardware.

many people (Linus included) see this as reasonable.

many other people (including RMS, and apparently you) don't.

personally, I do consider it reasonable. the hardware manufacturer is free to lock their hardware down. I am free to take the software and run it on different hardware. When there is competition (like in the Android phone market), I hope and expect that the drive over time will be to relax the lockdowns, or at least make it so that consumers can opt-out

remember that the same lockdown that prevents you from loading your own version of the software also helps protect the phone against rootkits. It's not the lockdown itself that's bad, the issue is over who controls the lockdown.

now, I also believe that I am free to modify hardware that I have purchased to disable any lockdown (and have done so on the several tivos that I own), I think the companies going after the modchip creators/sellers have no legitimate reason to do so, and I go out of my way to avoid buying from such companies.