First, since I think empowerment ethics is derivable, provable, understandable, and applicable all within the categories of the natural world that we all live and think within, I think that unbiased theists can (and even should) come to see its truth and wisdom just as much as atheists. Just as a theist can look at the world rationally, empirically, and naturalistically in order to do science effectively, so she can think about values, norms, and ethics rationally, empirically, and naturalistically to understand them effectively. While theists may think that the ultimate metaphysical explanation of the natural world is a deity, they can still grant that the world is knowable to secular people and capable of study according to reason and experience. Most theists don’t think that non-believers can’t do science.
And most theists accept that when doing science, it’s most revelatory to not invoke God but to figure out what naturalistic dynamics are at work in the natural world. So, theists who are not metaphysical naturalists who say that all that is is the natural world discoverable and interpretable by science, regularly at least accept the value of methodological naturalism whereby they think the world can be investigated when doing science in a way that leaves metaphysical commitments or beliefs about the existence of a supernatural to the side. Nature can be understood through methodological naturalism because it is naturalistic in character, even according to most of those who think that not everything is naturalistic in character and capable of study by science. So, on account of this, even religiously committed theists routinely bracket their religiously (or even philosophically) held supernaturalistic metaphysics and focus on what can be known purely within naturalistic categories.
Well just as theists can see that atheists can know about and rationally investigate it using methodological naturalism, and just as atheists can see that theists are capable of bracketing their supernaturalism and seeing what is revealed through a naturalistic methodology, so I think both atheists and theists both have plenty of experience correctly identifying differences between good things and bad things, and can both use plenty of available tools of reason and empiricism for working out what those are. Maybe the theist also thinks the reason the goods and bads we can naturalistically discover are as they are is because of some supernatural intention. But so long as they use naturalistic means for proving the goods and bad are a certain way that question of why the world is the way it is can be left for a different metaphysical debate. In other words, methodological naturalism can work just as well in ethics as in science if theists are willing.