Criminal prosecution is the civilized thing
The point of prosecution is that the government has to prove that you did a crime in a manner that requires particular rules to be followed. People are acquitted all the time (some news to that effect over here in fact). The US justice system may not be perfect, but it is no kangaroo court either. Ducking prosecution just leaves you 'beyond the law'... which is where vigilantism comes in. I think we would all really rather we keep with the civilized path to punishment.