What should be the punishment for asking, "Am I the only one who...."?

It depends, in my opinion. The structure of the question is intrinsically asking for validation. For harmless or even quirky things, it might be fine. But all too often it is being used by people who are overly obsessed with validation, and it is being used as a way to justify shitty behavior. eg "Am I the only one who steals candy from babies??"