True! and another reason to use BOTH moral arguments and consequentialist arguments to spread liberty. Also one may explore how Natural Law can be understood as either: the ethics that nature objectively tends toward, the ethics that nature requires for good x to be protected (life or prosperity), or the ethics that are a real objective thing in nature, even if only conceptually bootstrapped and arrived at by reason. Natural Law can be an appeal to all stances and there is no conflict inherent between these views of their own.
Discussion
I also think it's appropriate and normal to use both deontological and consequentialist ethics.
I never got much into Natural Rights Theory though.
I like what I've heard from the philosopher Michael Huemer.
He argues from an intuitionism perspective.
Basically arguing that we intuitively know that our life is our own without using much if any philosophical framing.
And that it doesn't seem to make any sense that the government should have any special authority over us unless it serves a very good reason.
The approach is clean, to the point, and cuts out any framing that's starting point based on an intuition anyway.
That intuition is, I think, one of several bases that are used for a natural law conception. The Anti-Federalists held those truths to be self-evident, after all.