Perhaps we're just looking at it from different ways, but as I see it, you are incorrect. There are just and unjust laws (and along a sliding scale: more just and less just) laws, but when the legislature - in our case - says so... yes, it IS a law.
I come to my conclusion mostly based on passages such as Galations 5:22-23.
22But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, 23gentleness and self-control. Against such things there is no law.
Almost the entirety of Christ's disciples were martyred because of laws against love, joy, peace, patience, kindness, goodness, faithfulness, gentleness and self-control.
Preaching the gospel is all of those wonderful things, and so is any other right worship of Him. Yet, the civil authorities had them killed for it.
So how can Paul say there is no law against these things, when there quite plainly is?
The answer is that so-called laws against these good deeds are, in fact, not law at all. And Christians are not just free to disobey them because they are unjust laws, but they are even
more free to ignore them because they are not law at all.