I posted something. Then I noticed that it was formatted wrong! I went back to fix it in edit mode. It seemed fine in edit mode. I saved it again. It was still wrong.
The thing that was wrong: In source / edit, my sentences are separated with the charcters "period space space". This is a typing standard that improves legibility, which is extra important in effortposts. However, in the displayed mode, one of every double space had been eaten! Every post, every comment, mangled! Sentences are separated with "period space" instead of "period space space" and the text is slightly less legible for it. I noticed it for questionmark space space and exclamationmark space space as well. There's some secret life form eating spaces.
Testing behavior: Period Space: Sentence 1. Sentence 2.
Period Space Space: Sentence 1. Sentence 2.
Period Space Space Space: Sentence 1. Sentence 2.
Yep, saw it in preview, all the spaces are getting eaten. This is a crime against good style. I won't go so far as to say this is a hate crime against anyone who struggles with reading and visual processing... yet. But the site is editing my comment in order to enforce an objectively worse typographical standard (period singlespace). Literally 
. 
on Communist Bear Site they automatically censor out your punctuation marks in order to make your writing conform to a worse standard, calling double spaces a bourgeois decadent waste of space.
Please help
(Also, should this go in /c/technology or in /c/hexbear? It's about both)
(Should I be submitting this as a bug report on github instead?)
This is exactly why text being controllable by the end user is always the best accessibility choice--not everyone's accessibility needs are the same! You're definitely not alone in preferring that extra space. I have had learners that have a much easier time with two or three spaces between sentences, and even a couple that preferred extra space between words.
Usually as long as the spacing was consistent the river problem was avoided. Though of course, many people never see or notice rivers, and that particular accessibility issue isn't one that touches their experience.
I hope you find an extension that works for you. I don't know any that add that extra space (though there are options in word processors to add that). Sentence Segmenter breaks lines after periods, so it's certainly possible for one to add space after periods I would have to assume.