Sloan is clearly not worried that Bashir will tell Sisko all about Section 31. This is partly because he knows Starfleet won't bother to investigate, but also because Bashir is playing into his hands nicely. Think about it: what happens because Bashir tells Sisko? Sisko tells Bashir to allow himself to be recruited. Sloan doesn't care how he gets Bashir working for him, and as Inter Arma Enim Silent Leges shows, Bashir is just as useful even when he thinks he's working against Sloan.
It seems a little unlikely that members of Starfleet would so crudely spit insults and accusations at Bashir before he's been charged with anything, even if they're members of Sloane's personal security detail. But then we learn that it's all been a simulated test, and those people probably don't even exist.
It's also an easy way to add to the stress of the situation, creating the impression that Bashir can't rely on the security officers' professionalism to protect him. If they're happy to insult him before he's even charged, while he's still on the station and under Sisko's protection, what will they do once he's on a prison transport and totally under their power?
Sloan really does seem disappointed that he didn't get to finish his test scenario, which begs the question of what the hell else he planned to do to Bashir? He's already (seemingly) gone through a false arrest for treason, threatened with prison, and had his friends turn on him... combined with Sloan's persona as an Augment-hatingInspector Javert with no oversight who blames Bashir for his son's death, it doesn't seem like Cold-Blooded Torture is off the table.
