> You are meant to press Ctrl with your right hand when you press C-x.

Nothing's stopping you from doing it that way, but since Steele and Moon started writing EMACS in 1976 on the PDP-6 and the PDP-10 and probably used VT52 terminals to access those systems, you're probably expected to have a control key on the home row to the left of the caps lock. The VT52 does not have a control key on the right side of the keyboard. I've found that Emacs's ergonomics are greatly improved by swapping the caps lock and left control keys on modern, IBM Model M-inspired keyboard layouts.