Just words. Not that hard, are they?
Proper spelling, capitalization, and grammar are more than mere style. An insistence on the use of these is an insistence on clear communication. (Helping Uncle Jack off a horse there, anyone?)
Being able to write with proper form isn't everything, though - I've read stories in fanfiction that are better crafted than some more recent published books. Even though fanfiction does seem at times like writing with training wheels, because the stories are already based upon previously-developed characters and settings (yes, even accounting for the alphabet soup of AUs). However, even the modifications some of these fanfic authors make to the 'toys' they've borrowed are more thoughtful than the development of characters in some newer books I've read. For example, while the description of sweat trickling down one's neck as the result of a hot meal is a stirring sensation to read about, is the host at that meal really so inconsiderate as to serve that kind of food to formally-dressed guests in the heat of summer, or is the author not willing to research cold alternatives that are appropriate to the time period? One is the author's active choice to portray that character in that manner, while the other is the kind of lack that no spelling or grammar check can fix.
That said, I still deeply appreciate an author who makes the effort to go through a story for the basic errors (or at least have it beta-read) before it comes out. There's nothing worse to me than to be jarred out of a good story by a misspelling that changes its entire mood, because it's easier to discard a poorly-done story than one I've already lost myself in.
Come on, author, is it really too much to ask for everything?