Although this race of characters is listed as fantasy or sci-fi, I am inclined to lean more toward sci-fi for them. They are very much dependent on computers and while those can show up in fantasy, especially modern fantasy, that doesn’t seem to be the case here especially when you add traveling the galaxy.
Now that we have established that, let’s talk about them. We know they are governed by a hive mind which immediately makes me think of the Borg, though the Borg would never wait fifty years of watching someone to pronounce judgement. They might travel fifty years to reach them and pronounce judgement, but they certainly wouldn’t wait.
We know that the computer they use was made by another race and that is the full extent of what we know of this other race. Did this other race do the same thing they are doing? Are they even still around? Were they judged by this race and destroyed, maybe the first race this race judged and then they found this computer system and found that it would be really useful for finding out more races that needed to be dealt with.
Perhaps the other race was commissioned. They could be tinkerers who like to make things and for a price or maybe a challenge they will make anything others want them to make. Either of these options could be interesting if someone wanted to go into the background of the race or made the computer system.
After the fifty years of watching based off this computer system, they still have more work to do, because at this point they decide whether the computer was right or not. It says usually they find the race guilty, but that also means sometimes they don’t. What might make them disagree with the computer’s assessment when normally they do? And what kind of punishment do they bring down. It being often severe implies that sometimes it isn’t and also that it probably isn’t total annihilation. What kind of punishment do you think they find appropriate that would be considered severe and when might they choose guilty, but not worthy of a severe punishment?