As someone with enough math background to be comfortable with one letter variable lanes and terse notation, this is still needlessly annoying to me because of the removal of almost all non-essential whitespace and grouping related definitions together on the same line instead of putting them on separate lines, and then using blank lines to separate "paragraphs".

I get it and I've heard it before, it's supposed to make it easier to fit more on one screen which is supposed to reduce cognitive burden. You are free to like what you like of course, but it just makes everything look like a jumble.

And even in a math context, I get frustrated if there's no simple glossary or surrounding prose to describe what's going on. Very few people write math this way, as a dense jumble of symbols. Even in the context of written mathematics, this is a very unusual style. I feel like J fans talk about it as if it's a totally normal thing to do if only you knew a little more math.