I have a similar view of disagreement - it is my belief that two rational people should, having the same information, reach the same conclusion. I don't believe in an "universal absolute moral truth" (after all, where does it come from, and why?), but I think humans share enough of their basic morality to make it de-facto universal for us. We should delegate only the bare minimum of it for the law to enforce, but the government is literally an embodiment of the concept of people getting together and agreeing on things, so I see no problem to it being a way to scale up what in small groups you can do through social customs.

> Can you provide one example of a law that should be enforced by a government?

I think you enumerated some examples yourself - "scarce resources, ownership, roads, defense, languages". Those things are suitable for being managed centrally, and management involves enforcement - even if you delegated most of it to the market, you still need to steer the market to do the job, lest it bails out when it's profitable to do so.