I guess it's a way to convey informality and rejection of "the norm" sacrificing legibility.

It's probably a way to express freedom, like the freedom of just refusing to consume unreadable walls of text that disrespect the reader. Freedom goes both ways.

I feel like the AI backlash is creating a rise in "authenticity signaling", cheap public displays of not using AI. Much like virtue signaling, it's lacking in substance and presents as an annoying affectation to people outside of the target in-group.

The journal is about a thing this person does privately for fun.

The writing style is clearly not meant for others to read either. They just did stream of consciousness out of their brain and didn't proofread. It's not meant for external consumption.

Capitalization is something you do out of respect for your reader, to make things easier for them. If you aren't intending others to read your writing, then there's no one to disrespect, so why bother?

.and some are putting the dot at the beginning of sentences with all lower case, like in Lojban .it makes much more sense if you think about it

(but i'm half joking here. normally i just don't capitalize, only the names.)

Let's say the average sentence is 17.5 words, with the average word length being 4.5 characters. Not capitalizing the first word is only a 1.27% character error rate, on average. Not too bad. ;)

I guess we’re so used to autocorrect doing that, so that disabling it is a flex now?

it's an intentional display of informality by the writer, i imagine. i do the same a lot of the time.

that's model talk! get 'im boys!