Since grammar is just an attempt to generalize observations about usage (descriptivist), when you attempt to correct someone's grammar you are really saying "th

Since grammar is just an attempt to generalize observations about usage (descriptivist), when you attempt to correct someone's grammar you are really saying "the prestige way to say this is ..., and you look foolish saying it the other way". In this case it is the author of the blog that looks foolish, since he is going in the face of the vast, vast majority of the community and he does not bring with him higher social status. This is all a long winded way of saying the author of this blog post must be completely insufferable in real life.