I've been in this Discord server called, "POLITICS" and I've seen the religious, theistic, specifically, Christians who assert that, since atheists commit apostasy (disaffiliation) from religion (usually monotheistic religions or religions with a supreme, ultimate deity), they have no moral backbone (moral philosophy).
It seems a little outlandish, after all, there are atheists who are nice and good (like literally any other person) so what's the deal?
One, religion isn't the father of ethics and the father of ethics doesn't need to be religion. The real identity of the father of ethics is simple; evolution.
There are Christians who say a thing about the "Judeo-Christian" values. It's been said a few times and this will hopefully be the last. Simply put, the "Judeo-Christian" values state that all
of the present-day moral values we have originate from the emergence of the Abrahamic monotheistic religions, Judaism and Christianity.
What are the implications?
Religion isn't the father of ethics, let alone Judaism and/or Christianity. Why? Before the emergence of Judaism or Christianity, were there seriously no morals to speak of? Morals don't pop out of anywhere. In fact, ethics date back farther than religion and mankind himself. There have been studies conducted showing basic altruism in chimpanzees. The experiment had chimpanzees have tokens that either favor themselves or a partner for a treat. (Proposers are the chimpanzees making decisions.)
In the chimpanzee version of this game,9 we limited the offers to two possibilities. Proposers could either make an equitable offer that rewarded both chimpanzees equally, or a selfish offer favoring the Proposer him/herself. We found that in 72% of trials Proposers made equitable offers, a percentage very similar to humans that make equitable offers (76%).7 Is this fair behavior? We believe so. For some reason the Proposers were motivated to achieve the same outcome as the one called “fair” in humans.
Basic altruism was present. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3656016/
) Why? This type of behavior, which would otherwise be able to be called ethical, is beneficial for a social species by preserving the group. You aren't going to see ethics in a fish nor a bear because those animals never had the capacity and most likely won't need to since they aren't social. This shows how religion isn't the father of ethics but rather basic social evolution. And this isn't even specific to Judaism or Christianity, religions like Islam also say this as well which is just wrong.
Once the Theist realizes this, they'll ask "Well, what is your moral backbone, still?". Before we move on, atheism isn't directly tied to ethics because we demonstrated religion isn't the "father" of ethics. Disaffiliation of a system not affiliated with another system doesn't mean we lack the latter system. Atheists may or may not have a different outlook on ethical philosophy and for me personally, it's an ethical/moral system/principles or philosophy that is fair, justified, and can really only benefit people as a collective and/or not limited to individuals as a social group (sorry for the lengthy description). This includes but not limited to Egalitarianism, Humanism, and Consequentialism.