And why are people accepting it, and even defending it?
As much as I've come to largely ignore the travesties of spelling, grammar & punctuation frequently plastered across the internet, this is still a sticking point to me - I can understand that it's sometimes inevitable, occasionally I can bring myself to understand how it's less bother, but why people think there's nothing wrong with it is beyond me. Alas, arguing the point is pretty pointless - nobody with poor writing skills is going to take the incentive to do something about it from a forum. All we can do is suck it up and hope they never pass on their ignorance.
As an afterthought, I don't mean any offence by the latter part of that paragraph. 'Ignorance' happens to be the most appropriate word and it's a shame that it carries such negative, offensive connotations, but I'm not willing to compromise literal accuracy for the sake of appeasement.