Incoherent misuse of the language of category theory. No one will buy in if the argument is not communicated clearly.
Perhaps the greatest irony of FP
BTW academic CT researchers are brilliant but usually aren't programmers
But the hate is warranted. Any new tech needs to be able to stand up to criticism
Functional programming theory has relied heavily on category theory ever since functional programs needed to do IO (around the late 90s), so it's fairly common for programmers to understand some basic category theory these days. After all, many things in programming aren't mathematical functions, so if programmers want invariants, then they do indeed need more mathematical objects than lambda calculus supplies.
A better attack on functional programmers would be that they cargo cult category theory - but I don't think the article author is in a position to make that argument.