It’s interesting that this doesn’t mention that the shell language is… well, bad. Even one of their examples has a bug: grep $CWD -in ~/.*shrc (which I assume has a typo for $PWD) won’t behave correctly if your pwd has spaces in it!
grep $CWD -in ~/.*shrc
This is why I’m considering switching to something like Elvish as my day-to-day; it has a lot of the same nice properties that POSIX shells does, but without all the badness. It also lets you pass around structured objects between commands, as opposed to forcing everything into text, which is one of my other big complaints with shells.
The first sentence does contain the word “reviled”.
(However, your comment made me want to at least glance at it.)