I'm going to play Sophie's advocate for a second (funny since she hates people playing the devil's advocate). It's in poor taste to talk about people from your support group. Anyone whose been in one for whatever reason knows those are supposed to be anonymous as can be. It would have been smarter had he not specified where he knew Sophie and maybe only give location-related proof and an explanation to a mod.
That said Sophie threatening to release the hounds on him makes her worse. She's a public figure who should know better than to use her platform to fight someone she has a personal beef with. (Seriously, at least send someone like him a message before crying to your fans, Sophie.) If the guy had not mentioned he knew Sophie at a support group I'd be completely on his side because I'm tired of seeing Little Miss Girl-Cock squashing anyone who doesn't kiss her ass.
(As for the high-school incident, Sophie can fuck off all the way. A kid talking about an event at their school doesn't threaten her, a nearly 30 year old adult.)