The party was thinking about the oddity that a slime race would bring. Not that they were hateful of them, the one who had managed to use slimes against the other races of Genesis was evil, not the slimes themselves. They had not caused the harm because they desired it.
Slimes had an important function within the world as a monster species with amazing adaptability. They had uses to the natural order of the world and were also numerous at times. They were both prey and predator allowing food a cycle in certain ecosystems to thrive. Without them the world would be missing a large portion of monsters needed to flow properly.
However, slimes had never really become properly sentient as a race. They had not developed in the same way towards sentience that any one would be able to call noteworthy.