> But it seems to be an extreme overreach for the FSF to use their license (and that “or any later version” backdoor clause) to start pushing their views on the hardware world.

Nothing is stopping the "hardware world" from developing their own operating system. But as long as they choose to come as guests to the FSF/GPL party, partake of the snacks and fill their glasses at the free-refills fountain, they're expected to abide by the rules. The doors not locked, they can leave any time.