I think the number of non-programmers who think 'I want to learn to program; I'll start with common lisp but emacs is too difficult!' is so small it is not a group worth considering. It's probably MIT & Stanford undergrads?
It's their IDE and they can design it how they want, but that's a weird goal for a CL IDE.
"It should be easy enough for" sets a UX bar, not a target audience. Kind of like the English phrase "X is so easy that even a toddler could do it," regardless of whether such a statement is figurative or literal.
I personally suspect that the overwhelming majority of those complaining would find a different reason to not learn lisp if the Emacs barrier were removed, but I very much might be wrong.
2. "Easy enough for a non-programmer" may also say something about how easy it is for a programmer.