** Not that I would expect it to work well; most people wouldn't consider the author a moral authority who's entitled to shame them. Behavior modification is hard.

Not a moral authority for most people who might stumble upon the post, sure, but I would guess that Scalzi is a reasonable facsimile of such of person for the audience of SFF fandom and con attendees at whom the post was more specifically aimed. He's perhaps not a "moral authority" but he is a person of sufficiently high status in that community that his words would carry some weight.

As for tone, it seems pretty typical of Scalzi-style prose, so again, for his main audience of fans, I don't know that tone would be a problem. The follow-up post linked on the page also seems to do a fair job explaining why the post is not just targeted to unrepentant creepers but also applies to people who may quite accidentally veer into that territory without even realizing it, and details how he has had to consciously check himself from doing so on occasion.