Probably, as not everyone is academic and or literate. Then you have to consider age, as with txtspk, that's the language of the young now, or at least it's becoming their written "speak".
Having written reports and documents for years in a military environment, JSP 101 was my bible (those in the military will recognise this document), where if there wasn't two spaces after a full stop or a space after a comma, would drive me into purple, perplexed maniac when red penning reports and documents .
Paragraphs that are too large drive me bonkers as well. Paragraphs should just be two or three well constructed and legible sentences and no more. More in a paragraph just makes me "scan" read and not take anything in.
Then there is paragraph numbering and lettering........................................................I could go on, but in conclusion, just because spelling and grammar are bad, doesn't mean the writer is a twit, just not as adept at the written word.
You're just getting old, old chap