Having started UNIX on Xenix, followed by DG/UX with twm like window manager, and an heavy XEmacs user during its heyday, I agree with the know-it-all college kid.
What exactly do you agree? That I'm not allowed to like my keyboard focused setup? That I can't avoid the mouse as much as I want? That he should be sarcastic with people who like to work a certain away after working for longer that he has lived?
But that's the thing - the article author is talking about a context menu, which by default means that everything from the context menu can be done by keyboard means.
As for me, I'm another greybeard that doesn't need a mouse, but defaults to using it over a keyboard-only setup. Keyboard shortcuts are great for things that are frequently done, but I'd rather not spend the time to remember rarely-used features.