Try doing some useful work after installing the Linux kernel – and just the kernel – on a device. You can't. You need more than just a kernel, quite a bit more

Try doing some useful work after installing the Linux kernel – and just the kernel – on a device. You can't. You need more than just a kernel, quite a bit more, and that's an operating system. "GNU plus Linux" or whatever you want to call it, or Android, or whatever. In that sense Stallman is correct that "the Linux kernel is just one piece of the operating system" (although his insistence on GNU/Linux is still rather wrongheaded IMO, but I don't feel like repeating that discussion).