Wouldn't that be the same argument for Apple hardware?

Sure, but where do you draw the line? Many PCs ship with some custom hardware but are not locked down. The MacBook Neo is probably not locked down but uses the same SoC as the iPhone 16 Pro which is locked down.

IMO it's pretty arbitrary. I wouldn't expect to run software on an appliance, even if the underlying hardware is commodity. And an appliance is something that performs a specific task (fridge, car, etc.). There are gray area cases though when an appliance does more than its basic function (smart fridge, car infotainment).