He shouldn't trust Pitch Black any further than he could throw a piano. But it's also not the greatest idea to insult him either. Or rather do things that Pitch then perceives to be an insult.

"That's because I haven't. It is not some great secret who I am."

To Pitch, "playing dumb" was akin to thinking that he was somehow stupid enough not to catch onto the ploy. In the fairytale sense he might be something of a trickster but he was far from harmless. Fear can be a great motivator but that still entirely depended on the fear of the one watching. This could still prove to be interesting, so Pitch ends up looking amused.

"What have you decided to call me?"