Long sentences are not the same as run-on sentences. It would behoove you to understand the differance before trying to make such claims. The entire reason paragraphs even exist is because it's not just a "me" problem with reading text blocks. Otherwise such blocks of text would be perfectly acceptable in pretty much any scenario and the vast majority of people would have no issue reading them. We don't live in that world, and if people want to be heard, they need to do the bare minimum to be comprehensible. If you feel shamed because somebody points out they can't understand you, that's more of a personal issue than anything. I don't see how people can't hit the enter key every few sentences.
"This sentence has five words. Here are five more words. Five-word sentences are fine. But several together become monotonous. Listen to what is happening. The writing is getting boring. The sound of it drones. It's like a stuck record. The ear demands some variety. Now listen. I vary the sentence length, and I create music. Music. The writing sings. It has a pleasant rhythm, a lilt, a harmony. I use short sentences. And I use sentences of medium length. And sometimes, when I am certain the reader is rested, I will engage him with a sentence of considerable length, a sentence that burns with energy and builds with all the impetus of a crescendo, the roll of the drums, the crash of the cymbals–sounds that say listen to this, it is important." -Gary Provost