On what basis is Hitler wrong?
I can demonstrate that rights come from guns, because there are some fairly simple experiments that you can perform over and over to see the principle working. Like the American revolution, for example.
Logically, please tell me how you go from, "rights are successfully enforced with guns" to "therefore, rights come from guns"? The conclusion does not flow from the premise...once again. Just because you OBSERVE a behavior works, that doesn't mean it is morally right. In fact, you just said Hitler was wrong - how??? Pragmatic is not synonymous with correct. If I rob a liquor store and get away with it, it works for me!
You can only claim that rights come from God, because there is no direct, highly pursuasive--even for skeptics--experiment that you can run to settle the matter.
Only logic and and your life experience. What more is there? Rights come from moral principles and moral principles come from God. How do I know? Two ways. First, the ONLY alternative to moral absolutes is moral relativism (by default), and I can show that relativism is illogical and that no one (except the psychotic or mentally ill) can live like a relativist. Second, moral absolutes are logical and fit right in with human experience and behavior. I CAN and DO live as if moral absolutes exist, and SO DO YOU.
This reasoning works for you because of the implicit assumption that if it is Moral it must arise from some cause that isn't simply the pragmatic long term interests of the group. This is what we used to call Post Hoc, ergo Propter Hoc reasoning in rhetoric class: assuming what's to be proved. Pragmatic is synonymous with correct from my point of view, and is all the source of morals one needs. It's just fallable, is all. Like has been said about democracy, it sucks, until you observe the track record of all the available alternatives.
On the same basis we cling to, for instance, the first amendment. Free speech for everyone, not just those who agree with me. It's a prudent idea with long term benefits for all who subscribe. Guarantees of life & liberty for the innocent, ALL the innocent, not just those who worship at my church. It accrues to the long term best interests--the survival values--of the entire polis, the entire country, the entire planet. It's a good thesis with widespread applicability, no matter what you decide is your primary survival group.