Even if it fits her personality, getting into a romantic relationship with a "fan" would be a new low, even for her. That's why I wouldn't mind a little more confirmation before I accuse her of that,.
It's certainly a possibility, but if he really is as bad a simp (and a mod too), then you would think he has no say in the matter. She does whatever the fuck she wants to, and if you don't agree with it you're an a-hole. The last bf may have been a prick (at least that's the impression I got), but he at least he stood up to her. If she really is dating a "fan" then you know that's not going to happen. Ever.