I wanted the Peloran to seek peace in all things as their primary genetically encoded mission. They only fight under orders or to defend their life, and since their creators are dead, that leaves defense. The rest of the galaxy is perfectly happy to leave them alone. The trick is that two millennia of genetic drift has caused a slight shift in their genetic imperatives. Some few members of their race are capable of going out in search of someone who wants to start a fight. They are the ones who walk into gang territory and wait for the gang to come deal with them. They did not start a fight. They were just standing on the corner minding their own business.