It does come across as a bit glib, but I empathize with the author.
I worked in legal higher-ed for a long time; I have absolutely no legal education, but my job involved reading lots of writing about the law, both for expert and non-expert audiences. Accurately conveying the importance of a topic without getting into the nitty gritty or running into collisions with colloquial and legal word usage is tough. Even that one paragraph I quoted had like 6 citations or something, and that's not just to satisfy technical requirements. There's just so much subtlety behind even very common words like may, must, shall, and will when used in a legal context that it seems like context switching is tough. The word count seems to grow logarithmically with the factual and conceptual detail, and even then you're leaving out a lot of padding beneficial to laypeople. We ran an open database of caselaw and we regularly got questions from well-meaning folks trying to inform themselves about some legal predicament by reading the cases, but it's just not feasible. Lots of folks argue that the whole thing is just based on shitty writing practices and gatekeeping legal knowledge, which might be true, but the difference is still consequential now. I actually think this is one area generative AI will be a huge boon, though I was skeptical until pretty recently.
Also, accessibility is a concern. Lawyers doing this sort of work are often very concerned with making their work useful to general audiences. Since subpar access to educational resources and cognitive disabilities are over-represented among low-income people, they're the most heavily affected by this. I wouldn't be surprised if they avoided a lot of nuance assuming curious people would just read the brief. I imagine they'd have written it differently specifically for a largely college-educated professional crowd, but I can definitely see why they didn't.