Once one has enough power and experience to achieve one’s goals despite opposition, and to use others instrumentally, the moral calculus can become difficult. We do not all start from the same circumstances: I am writing this on a phone produced by slave labour.
As Lenin might have said: “compassion for whom?”
You say “God is a choice”. Solipsism is a choice.
Is your position that compassion is only possible via religion?
I don’t think religion is the only path, but that it has functioned as a prosocial positive-sum cooperating/compassion technology/mechanism in many cultural contexts. Not without downsides, of course.
That many today relatively reflexively default to ~‘we can all be nice to each other; this is obviously the (only) moral approach’ without stated precepts/priors/fundaments upon which that morality is moored I think tends to implicitly borrow priors from Western Christian tradition, albeit incompletely and sometimes critically so. Sam Harris’ recent appearance on Ross Douthat’s ‘Interesting Times’ podcast was IMO an example of this.