Your argument makes assumptions about how I would approach things with your number 1 argument being that *someone* must be allowed to initiate force. So of course, attacking a straw man is easy. I do not advocate trials of public opinion as you suggest: it does not scale, and is not just. I advocate consent of the governed where every Keyhotee ID publicly signs which laws they will follow and by which agencies they are willing to be judged. Then phone software can validate that two people have compatible systems of law and dispute resolution before you do business.
Of course there is injustice insurance which to qualify for you must also agree to certain rules and post collateral on your own behavior. People are only systematically shunned when they are found guilty of violating a law they agreed to follow by a court they agreed to submit to.
Note: if you assume that someone must be allowed to initiate force you automatically limit your creative problem solving ability by limiting your search space.
I take the stance that it is not necessary to initiate force based upon a very simple premise: "don't do unto others what you don't want them to do unto you". From this position I do not want any one to use violence against me just because they think I am guilty or because a court they select found me guilty. Even if I am guilty I don't want force used against me.
As soon as you give even an inch and grant someone a monopoly on initiating violence then over time that institution will turn into what we have in the USA today. Now you have to decide who is exempt from the law and who gets to make the final call.... they will use this power to exempt themselves. Then the laws will start to become arbitrary as well as the court decisions. You remove market forces from a situation and quality declines and prices increase. You then necessitate taxes to fund your laws and thus implement a socialist justice system where new victims are created to punish perps.
Bottom line... I may not have the solutions yet, but I believe there exists a structure that will allow the vast majority of good men and women in the world to secure their life, liberty, and property without resorting to stealing from each other or stooping to the same level as the very people they are trying to stop.
Idealistic? Maybe... something to strive for... definitely. Impossible?