I'm showing up late in the game, and there isn't a lot to say that hasn't been said. I pretty much agree with MadJSimon.
The story is definitely science fiction, but it lacks a sense of wonder, which is why I, personally, read science fiction. I still don't like being preached to, even if it's an alien who is doing the preaching.
I found the Americans insulting. Could any other group have been portrayed so stereotypically? True, we've all seen ugly Americans in our travels, but they stand out only because they are louder than the peace corps workers, English teachers, and backpackers. This had the effect of putting me on the defensive from the beginning.
The story was about the tour guide, but I found him unlikeable. I agree that a more interesting story would be to tell what brought him to this level. As it stood I felt like I was being blamed for the sorrow of his country. If the story were about him, why did the family have to be such jerks? I felt like I was listening to four people competing to be the biggest prick.
Though having said that, I found the characters of the Americans more sympathetic. Maybe it's because I was on the defensive. The mother was open-minded and curious, the boy knowledgeable and intelligent, the father realistic and skeptical -- rightfully so, we discover. These are traits not all cultures admire, but the West does, and I think all of us do, too. The tour guide was arrogant, racist, overly religious (IMHO), and deceitful. So now I've talked my way from "stereotypical" to "nuanced." But there was still a heavy enough dose of ugly American to put me off.
I would like to say that it is a real and rare treat for the author to participate in the discussion. Thank you, Mr. Resnick. I don't mean to bash your story, these are just my feelings. I understand that a lot of people thought it was great.