If they chose to obey the golden rule that would simply be their personal preference. Or they can chose Power, per Nietzche, and that would also be a personal preference. Neither one is better than the other, its simply a choice, and in the end who cares what the choice is as we all end up in oblivion anyway.
In any case, Athiests are responsible for the worst genocides of all time, Stalin, Mao, Pol Pot, Castro etc. And that makes sense given that, in an Athiest world, anything goes to get the job done, and getting the job done is considered “good” and “moral.”
Atheists are accustomed to Christians being polite as they attack them. I match their energy and they run like wounded dogs. They freak out when a Christian puts down the Bible and looks ‘em straight on. I don’t want to convert activist atheists. I want to crush them.