It's not what I read for primarily, nor did I say so. Your supposition is something of a strawman argument. There's no need to be defensive on McCarthy's behalf. Any writer receives much worse criticism than that no matter how good they are, often from themselves. We tend to be our own worst critics.

That said, poor grammar pulls me out of a story and that's a common reaction.

A good writer might use such run on sentences sparingly as a matter of style, to good effect. William Kennedy's opening paragraph in Quinn's book is a good example. The quoted passage from Blood Meridian may be another such. As I said, I haven't read McCarthy and don't know if such run-on sentences are typical of his writing, so I asked.