that as the case may be, the same argument applies to vim (i use vim, with at least some of its keyboard shortcut glory, and love it); it might be faster in a lot of cases, but at the end of the day editors like sublime, atom, brackets, etc all have a much larger user base because people aren't willing to learn
No, they're criticising tmux as a proffered alternative to a full-featured terminal emulator, which is often used by non-power user programmers who are not willing to learn (like me).