You make a really good argument. Especially the external binaries part convinces me that shell is much more on the facetious end of that response spectrum.

I would argue that it is unfair to compare different implementations of shell, though. I think it's fair to compare across versions of bash, for example, but disingenuous to compare, e.g., Dash, Bash, Ash, and Msh. If, for example, Dash is my target, then I should call and install Dash. For this reason, it was probably a poor idea for me to call out /bin/sh, specifically, as custom dictates that this is, in fact, a different program in different environments.