I should not complain as sometimes a lazy advert can work in a buyer's favour.
I've certainly picked up some absolute bargain used bikes where a poor description, photos, and/or spelling has worked in my favour.
40% of Army recruits have a reading age of 11 years. This may be similar for skilled manual jobs like plastering and bricklaying. I would imagine poor readers are not good writers either. I have no objection to this as society needs all those trades to survive and whilst I can read and write (just), I can't do any of the manual jobs above. So I have no issues at all with bad English or spelling in adverts as long as the content is present. Sometimes it is laziness but I can't prove this when the author may be trying their best.
Interesting observation about the army recruits. I can't say I'm surprised, as military service has always been an option for those whose civilian career choice might be somewhat limited.
Poor readers aren't good writers. I work with someone who can barely do either. He can't make any sense of any technical diagrams either. I suspect he's dyslexic and didn't achieve at school because of that, because he clearly isn't actually thick, and so long as he's working with someone who can deal with paperwork he gets on OK. You just can't leave him to get on with stuff by himself..