"Objective" means derived by fact, irrespective of opinion. Ie. you lay out the foundations of mathematics, then argue 1 + 1 = 2. Objectively true.
There's no objective truth in "killing is bad" (killing Hitler clearly isn't) or any other morale statement. Objective morale philosophies (Kant, utilitarism, etc) to my knowledge are all contentious and competing which as far as I'm concerned just shows that they aren't objective.