If "natural" is the opposite of "rare" and means "common," it has no critical bite. Unless you think it's wrong to excel. If it's the opposite of "artifice" and means "what we haven't altered," it has no critical bite. Unless you think people shouldn't wear eyeglasses. If natural is the opposite of "supernatural" or "miraculous" and means "can be explained in the ordinary ways," it has no critical bite. Unless you think only divine intervention is wrong.
Just so. But theists shouldn't identify this silly position with "naturalism" in ethics. Ethical naturalism is not the claim that morals are found by looking to (biological) "nature". Rather, it is the view that ethical properties are (metaphysically) naturalistic properties - or, more simply, that the natural facts determine the moral facts. This is a very different matter!
Happiness, desire-fulfilment, the achievement of goals - and everything else that happens in our worldly lives - all count as "naturalistic" in this sense. So well-being and harm can be accounted for in naturalistic terms. And since morality is about advancing well-being and preventing harms, we can offer a naturalistic foundation for morality. This is what ethical naturalism is about. Not that "X is unnatural" rubbish. So please put the straw men away.