The poster wasn't directly calling another poster a narcissist. They weren't even directing the term at a specific person. It was just a reference to some people that may turn up. It's like saying, "there are real jerks on the road today." Also, I'm quite sure that many, but not nearly all, selfies are taken narcissistically. I mean, it is literally gazing at your own reflection, as Narcissus did.
That said, it is a negative term, and it does not in any way rhyme with "selfie stick." Those must have been some bad writers at the Warehouse.