I don't recall him writing about pickup artists, tbh, but the allegations here include some behaviors that were never considered acceptable (as in outright sexual assault).

StillStackinAfterAllTheseYears

mostly_harmless

John Scalzi: Please Don’t Idolize Me (or Anyone, Really)

Wow, NG has had some interactions with the pickup community. Wrote a book on it IIRC, but to be a predator? I don't want to defend the guy, but this seems to be common practice nowadays to pick up on someone famous because of some behavior that was once accepted and now it's something one could possibly capitalize on...