But that piece of information came from Sloan, yes?
Everything that came from Sloan's mouth and his brain, is suspect.
Sloan claimed that Section 31 *does* have legitimacy because it comes from Article 14, Section 31 of the Starfleet charter.
So by your own logic, why should you believe him when he says THAT, eh?
Especially when ENT revealed that the Starfleet whose charter that is, was the Earth Starfleet, not the Federation Starfleet. And in that case, it wasn't any S31 operative who pointed that out, so you can believe that part.