> those have not traditionally been on any keyboards
Appeal to tradition, not a real argument.
> it's faster to use a single key.
This isn't self-evident as you make it out to be. Depends on keyboard layout and the typist. For me it's usually faster to press a combo than reach for that far-flung dedicated key.
> Yes, I can press FN+Backspace to do a Delete... but why when it's such a common operation?!
That's arguable, and even so, I don't see why it's worse. It even makes sense that a modifier alters the direction of deletion. Notice that on the mac keyboard the backspace says delete on it, not backspace.
> What I don't understand is how Mac users put up with this!
Maybe Mac users honor their traditions?