The debate usually gets framed as: can nonbelievers be kind? Of course. But that's not the claim. The claim is that moral obligation, as binding and objective, can survive without a transcendent source. I don't think it can. Take Plato's Euthyphro: either the good is good because God commands it, or God commands it because it's good. The second horn leaves goodness floating above God, which just relabels the problem. The first at least grounds obligation in a personal lawgiver. Aquinas makes this explicit in the Summa: natural law is a participation in eternal law. Strip that away, and you're left with Hume's is/ought gap: facts about harm or happiness don't by themselves generate a "you ought." You can have preferences, conventions, and empathy, but not moral duties that bind someone who rejects them. So secular ethics can describe cooperation, not obligate conscience.