Agric: What do you want me to say? Tha I will raise an army to oppose you and we will have a bloody and destructive Civil War while the Rebels snatch planets from under our noses. I am offering you the chance to destroy the Rebellion and the Jedi once and for all.
Drago: Ten thousand dead are not a small problem, nor should they be brushed off lightly. *He holds up his hand* Do not tell me millions could have died, I am aware of the questions of scale here. Regardless, the only reason for withholding information about the Heloki would be if you wanted to use them, or something like them, against us in the future. Further, since you have dumped this in our collective laps for perpetuity and without warning you owe us at least this information. We could fight them without it but that would mean higher casualties and a larger group might even break containment.
If you don't want to give information about your own movements and operations then fine but you have no reason for witholding information on the Heloki themselves.