rilchim, while I’m not a big fan of judging people and all, I think you’re going a little overboard here. In fact, you don’t need to stand looking at someone for minutes on end to size them up. You look at them, you get in the car, you still have the ability to size them up and draw conclusions for yourself.
At the outset, Scylla wasn’t yet sure what she wanted, and it would have been very rude to just get in the car before she even said anything. Then, she asks a really weird question. First instinct is “what?” like maybe the question wasn’t heard correctly or something. Then there’s the response, but by this time all the alarm bells are going off, so he gets in his car. Doesn’t seem overly snobbish. Just seems like he was kind of weirded out by a strange encounter and wanted to get away from it after je realized just how strange it was.
Yes, everyone has a tendency to categorize people in their minds. Sometimes we don’t express what those categorizations are, so as not to offend people. What I’m trying to say is that it wasn’t my impression that he acted snobbish, just that he was really weirded out by an abnormal encounter with a walmart martian 
