Fully agree. Is Mars such a hospitable place so that you have to think of a fake reason in order to get somebody in a story stranded on it?
I read the interview with the author; previous poster mentioned it. Basically Weir said that this book was essentially man vs. nature, and he wanted "nature" to strand the main character to get the story going. Pretty understandable to me that when creating a story, you need to take some creative license.