If rights exist, how would they exist if they are not immanent?
Immanence is basically the theory of divine presence in philosophy, IIRC. You can postulate divinity on any number of levels, from the strictly local (such as a typical Roman emperor ) to the regional (such as Greek gods in the Roman world) to the universal.
See how this works? A "right" can easily be defined in a context and still be outside mere legislation, if you choose to argue from that viewpoint, but does not have to be universal.
Now, you can postulate that some rights are universal instead of regional or local or whatever other definition there might be (including that there are none, btw), but if you do that, you'd better build consistency around what you postulate because it's not something that is obvious.
And never mind that you start from the theory of divine presence when the people you are talking to tend to reject that presence.