I tend to be more forgiving to the average person screwing up a loose/lose proposition. Writers, however, do not get a free pass on this one. It’s like an accountant not knowing the difference between subtraction and division. It’s like a pilot not knowing the landing gear should be down for landing. And while the consequences of poor grammar cannot be equated to a pile of aluminum on the runway, in terms of professionalism and advancing a writing career the implications are the same.
It bugs me any time I have to fix a typo here on 512 Pixels. When I have to correct a grammatical mistake, however, it kills me.