First of all, the existence of a social norm is different from a law, and we were discussing the former, not the latter. It's true that if you have reason for a social norm, you might have reason for a law. But it may be that the norm would be overall beneficial, and the law overall harmful.
If having a norm or a law against something means that people are not agents, then people are not agents because there is a law against murder. So obviously that does not follow. If you want to call that "taking away agency," you can, but people are still agents.
Are you saying that society would be better off overall without any norms or laws? And would you push a button to bring about that state of affairs?
To push the button in your scenario I would have to be very certain that it would be beneficial overall, including the fact that I was pushing a button like that. I am not that certain, so I would not push it.
I've started a podcast called Future Strategist which will focus on decision making and futurism. I have created seven shows so far: interviews of computer scientist Roman Yampolskiy, LW contributor Gleb Tsipursky, and artist/free speech activist Rachel Haywire, and monologues on game theory and Greek Mythology, the Prisoners' Dilemma, the sunk cost fallacy, and the Map and Territory.
If you enjoy the show and use iTunes I would be grateful if you left a positive review at iTunes. I would also be grateful for any feedback you might have including suggestions for future shows. I'm not used to interviewing people and I know that I need to work on being more articulate in my interviews.