Rhote says, "Brother, leave them be. You may one day rule this land and we do not know how many non-humans reside here, nor do we know which of those might rise to oppose you. Plus, our current enemies are human, meaning that we might be fighting an internecine conflict ourselves. If we begin to succeed and slay non-human tribes outright, we may face a combined uprising of those fearing extermination. The kobolds at least provided us with intelligence we can use. We now know a bit of their history, about the Mites and of a possible magical artifact, which might be valuable information indeed. None of this would have been ours if we had slain them outright."