...but I do expect that people show some sort of intelligence...
Well, you may as well lower your expectations. Most people are lazy.
Standards for writing seemed to have dropped considerably
over the past few years.
Even CNN & MSNBC are guilty of this, but no one seems to care.
As long as it's not being pointed out to writers, it will just become more and more accepted.
I think Carol has described this before as, 'entropy'.
Personally, grammar & punctuation errors only bother me if I sense that a post is inconsiderate to the reader, in general.
Infrequent errors are inevitable, but lack of structure, rambling, etc., are signs of thoughtlessness IMO.
It's the writer's job - not the reader's - to make a post or article understandable.