I dunno. Acting grumpy because we feel disrespected, while continuing to display casual awareness of information that would be momentous by X-COM's standards, might well help establish our bona fides.
Anyone remember the fable, The Princess and the Pea?
An outside agent working for the Ethereals, but posing as a space princess, would be very calm and sensible and levelheaded. Because everything they do, they do for the sake of an overriding plan to infiltrate, and they're almost certainly going to subordinate their pride to the plan.
A real space princess, by contrast, has expectations.
I would rather be casually scary than deliberately self-destructive. We make it obvious that we know we're talking to XCOM anyway. That itself shows information capabilities so good that we treat them as routine. If we save a name drop until the end of the conversation it puts the same pressure on them without destroying the flow of the negotiation and changing the other party's attitude.
Remember, we really want to be taken seriously here. The more serious they treat us the more they'll believe us and the more things we can negotiate for. Acting a child will close doors.