Linux is a kernel, and Linus has all the right in the world to make that claim. It doesn't in any way strengthen your argument though because of the different userland. You are comparing apples (operating systems) with oranges (kernels).
I tried to tell that his "real-Linux" (kernel) already exists (I don't know if he meant (in another comment, he said that he meant userland) userland e.g gnu, freedesktop.org etc by "real-Linux")
