Do they? I feel like a "citation needed" is in order.

There's a target for math formulas, and it's mathematicians. Those can read math formulas, even advanced ones. If outsiders (that is, laymen) can't read them, it's ok: they aren't supposed to be working with math most of the time.

The target for programming languages is programmers. But unlike math formulas, the outsiders that can't read some language J isn't laymen, but still programmers. The problem is not that non-programmer Joe Sixpack can't read J. The problem is that programmers can't read it, or find it unyieldly.

You could argue that, 'that's ok, the target for J is people who comprehend and are productive with something like J'. Sure, but that's precisely what we call out here. That some languages, even though expressive technically, put off not just outsiders from programming, but also programmers.