I think the correct term would be 'specist'. As in, the Solomani are against other alien species, not races. (scifi tends to forget there's a big difference between the two)
I don't know what the basis for that is, but if you look at it: the K'Kree want to murder all meat-eaters, the Hivers are grandmaster manipulators, the Aslan are like Kilrathi (warrior race bent on landgrabs), and the Vargr have raided human planets mercilessly and ruthlessly.
Or in other words, xenoc scum.
And ask yourself this honestly. We tolerate many dangerous animals on this world, but what would happen if something like a Lion or Crocodile were intelligent, semi-aware, and capable of tool-making to the same degree as we were thousands of years ago? What if they were as intelligent as we are, completely self-aware, and could use the tools we make for ourselves, like today, RIGHT NOW?
Two species competing for resources, and it gets ugly. Scifi often uses the human vs alien theme as a way to explore race issues, forgetting for the billionth time that alien speces are not analogous to racial hatred, because they're not a separate race to us! You can't imagine the Narn as blacks and the Centauri as the British, because it DOESN'T work. You literally have to think "well what if this animal that's looking at me like I'm a happy meal on legs had a rifle pointed at me?"
Sometimes you can look at an animal and go "Yeah, we'd still be friends" and you get an alien race like the Vargr. Then you look at something like the K'Kree and think "...Hmm... PETA crossed with a horse, now they can chase me down no matter how fast I run. Boy, I hope they didn't see me go into KFC.. oh damn, they just kicked out my spleen. I guess they did... oh whoop, there go my lungs. I'll die soon."