I'm not arguing with what you're saying, but it does make me wonder: What exactly is the point of the status page, if "it is normal for users to already see errors before GitHub officially counts it as an outage"?

Is it more so to have something to link to for managers who aren't using the service have a pretty bar to look at and feel like they are "doing something"? Or is it more of a kind of a way to prevent confirming what you already suspect to be true. E.g. "Huh. Me and Jim are seeing problems. How about you Tom? Oh wait, crud. The service page is confirming it's down now. Never mind! Who wants coffee?!"