Why does the Classical View on Human Nature explain their reasoning on not Rejecting the State Completely?

-Their view on Human Nature is that Humans are Selfish and Uninterested in the Welfare of others. Thus it leads to a Belief that the State only needed to Protect us from each other -Because of the Belief in Negative Freedom, the State must be Very Restrictive. But it's better than Anarchists. They reject the State!