"Grammar? We don't need no stinking grammar!"
That really bugs me as well. Yes...my grammar sucks on occasion...but I am not a professional word-maker-person. You'd think that those who write for a living would take the time, and have the professional self-respect, to do it right.
Unfortunately, I have seen too many people in other threads right here on MR talk about how spelling/grammar/punctuation don't matter..."it's all about the story".
I think the spelling/grammar/punctuation is HOW the story is being told. If that is bad, I don't want to (can't) hear/read it...it distracts too much from my enjoyment.
Just imagine Charlie Brown's teacher reading the Lord of the Rings out loud....monotonous, dull, can't understand what is trying to be said...that would turn off even the most diehard "ringer".