I understand what you're saying, but the problem I see is that at what point is it any individual's prerogative to decide that he doesn't want to obey the laws of the land? Like you said, not eating fish on Tuesdays may not be a big deal, and if a person who wants to eat fish on Tuesdays decides to do so anyway, what difference would it really make? The results of one individual breaking other laws he disagrees with may be a whole lot more serious. Take a law such as speeding, for instance. Suppose the laws regarding how fast we could drive were determined by a religion. If someone decided that he didn't like being restricted to driving 65 miles an hour and wanted to drive 95 miles an hour instead, would that be okay?
Depends. What's the design speed of the highway?
Stopping sight distance and the coefficient of friction for rubber on asphalt don't change with a person's religion.
Also, I think the question of seriousness works both ways. It's not just a question of the consequences of breaking the law, but also a question of the consequences of the law itself.
If Meow Mix's hypothetical religion was in charge and I couldn't eat fish on Tuesdays, it wouldn't be a whole lot of skin off my nose.
If I was forced to follow Mormon practice and I couldn't have coffee, this would be a bigger deal, but not the end of the world (...as long as I can have Red Bull instead - there's nothing in the Doctrines and Covenants about Red Bull, is there?
).
OTOH, if I lived in a Jehova's Witness-run society (which I suppose would be a bit of an oxymoron since they avoid political involvement... but just for discussion's sake) where I could not get a blood transfusion, this could potentially be a very big deal for me indeed.