I see this argument made from time to time. Perhaps it’s my lack of understanding as you say, but if you think your concept is a good idea, I would urge you to look at places like Somalia and how gangs have been elevated and warlords rule the day.
It would take about ten minutes before our cities would devolve into total anarchy.
What you are effectively saying is that the liberties of a free citizenry are completely incompatible with an urban existence. I won't argue with you on that one, but that goes back to whether a constitutional argument has any place in the discussion about the Gates incident at all.