Maybe he was like the 20th person that day to approach Ralph to chat or try and shake hands. I'd have to imagine it would become pretty annoying after a while. "Celebrities" are just like normal people in that they just want to be left alone to do there own thing sometime.
I saw Kareem Abdul Jabbar in Maui a couple days ago. Would have loved to get a picture with him but he was on vacation just like me. I'm not going to bother someone who is just trying to live daily life.
Maybe if people just left public figures alone in public once in a while they wouldn't have to appear as !@#$s when they get annoyed about being approached.