In the ordinary course of jurisprudence, jurors should not try law.
That they have the authority to do that in the Common Law I do not dispute. Nor do I disapprove of it in cases where the law is repugnant to common sense or the consensus understanding of our Constitution [or constitution.]
That said, those are extraordinary circumstances, and in the routine practice of law, juries should not try law. That is what you are advocating, and it is a short road to legal chaos and all manner of criminal misbehavior by law enforcement and prosecutors.
I disagree, if the law is good there should be very few who would dissent to it: e.g. how many people think there should be no law prohibiting murder?
Virtually none, because it is universally recognized as immoral.
How many people think there should be no federal law prohibiting, say, drugs?
Quite a few — indeed you cannot be a constitutionalist and a supporter of the War on Drugs simultaneously, precisely because the justifications for them are rooted in Wickard (saying that congress may regulate intrastate commerce because it impacts interstate commerce); they [the USSC] has even said that noncommerce is, in like manner, under the purview of congress (Raich).