After a significant amount of interrogation, the Terminus Regiment found that the Grax population was the last of their kind, a species on the run after another planet's residents had overthrown them, presumably for the same sort of thing that they had done here to the humans.
Their attitude made it both more difficult and more pleasurable for the interrogation specialists to work, as they actually believed that their technology had made them gods. In their minds, that was all it took. If you could force others to do your bidding, you were their god, end of the story. So, they believed that they had every right to do what they pleased and that humans should remain below them.
That explained a lot about their attitude at the negotiations for territory. Max hadn't been able to pinpoint their attitudes among the crowd and had thought that they were merely arrogant. Seeing them here made him realize just how delusional the Grax really were.