Exploitation is the extraction of surplus produced by the working classes by the private property owners. In other words, it only exists when someone extracts surplus from *somebody else's* labor. In a communist society, society produces the surplus and extracts it for its own benefit. By that definition, social labor in communist society hence cannot be called exploited labor because the products of social labor belong to the producers of the social labor -- just some of that social labor directly belongs to the producers whereas some of it belongs to them indirectly through social services.
