That's not what I read at all.
He posted
and received several replies, one of which from Guinness Boy was "good evening Mr Gooner", so Guinness Boy was the fire-starter.
Unfortunately, this happens on here as it does, to a much greater extent, on twitter. Like-minded folks with a history of favourable online interactions will gang-tackle a newbie who "steps out of line". Really, it's just done for amusement.
I've no idea whether he's a Brighton lurker or an...