Hell, I spent time stuck on a problem because I had never used code folding before, and couldn't find the import statements I needed to edit.
Would you agree that not understanding code folding is a bit much?
I'm not defending the particular individual, or the situation, only giving some context to my comment.
Not knowing the copy and paste keyboard commands is a completely different realm of incompetence!
But you're right that lots of developers don't know many keyboard commands. I was being a bit too broad. Personally I can't imagine how any programmer would not bother learning keyboard shortcuts (or even better vim keybindings), but I've met plenty who didn't.
That being said, while using the 'edit' menu to copy/paste is clumsy, I don't see that it would actually have a significant effect on someone's productivity. So I would not go so far as to say that someone was incompetent just because they did that.
I do think that he might've had a chance (perhaps downgraded to a junior position) if he'd shown willingness to learn though. The fact that he just sat there for two weeks pretending to be busy was the primary reason he got let go.