Please understand, we are not completely inhuman with our obsession over grammar. In the end, we too are simply looking at the story, but, when the grammar mistakes are obvious, and certainly mistakes that a basic understand of writing would have fixed, then we simply cannot over-look these mistakes.
Fixing this is very easy, especially with the tools available to you within most writing processing programs. For example in MSWord 2010 using the grammar and spell checker can find an amazing amount of the problems. You might not get all, but at least you will get close. It goes like this: