I have no idea what game you have been playing, but in Avernum: Escape from the Pit the sliths clans vary in ideology and the main difference as far as humans are concerned is the division between clans of two types.
Group A: Friendly folk who trade with the humans, are not at war with the humans, and whose villages you can visit (normal towns only with sliths instead of humans).
Group B: Vicious speciesists who believe non sliths sophonts (humans, nephil, etc) are to be hunted down for food and sport until they are all exterminated.
Group B is the one the avernites are at war with.
The tribe where the egg encounter occurs is led by an extra zealous shaman who has personally been leading raiding parties to terrorize the local humans. In fact, those humans he has captured he makes sure to have butchered for food (exact specifics left to our imagination) on the shore where the humans on the other side of the lake can watch and see but be unable to act (thanks to water superiority of the sliths).
That I agree with, even if finding human adopters for them is hard they can just be delivered to the peaceful clans instead. I really think such a quest should be added as an option, as well as possible consequences with the peaceful slith tribes if you go for slaughter.
As some have pointed out though the "smash the eggs" thing is not as black and white.
Those are unhatched eggs in a village you just personally depopulated (or at least so you thought until the hunting party returns).
he young are going to be eaten by a predator, if by a miracle they hatch they will starve, if by a miracle they do not they will have no one to teach them even something as basic as language, totally feral like animals.
If however a hunting party survived, then they will instead raise said young with their ideology of slaughter as well... so given the choice between "do nothing" and "smash eggs" I go with smash eggs... although if this was real life I would have instead opted for "take them and find someone non evil to raise them" (heck, I'd raise them myself if I wasn't busy saving the world)