To begin with, it is important to state one truth; that is, all comic book heroes, unless sanctioned by the government, are vigilantes. Superman, Batman, Spiderman, and now even Iron Man and all those who registered with the Superhuman Registration Act. When it comes to their acceptance in their own worlds, it depends on the writer, instance, and overall atmosphere. Superman is worshiped, Batman is respected, Spiderman is hated. Of course, it goes without saying that these characters are fake, along with the worlds they live in. But what would happen if people began dressing up in costumes and fighting crime. What if someone took things too seriously, and went out on their own. How would we act?
Much depends on their own actions. If they killed or simply captured (with some fighting), if they protected those being hurt, or went out looking for a fight. In some ways, this person would do good, they would be able to intercede where the police could not, be out on the street, saving victims.
Assuming this "hero" did not kill, and protected those who cannot protect themselves, than they would have my full support. In a lot of ways, I believe they would inspire good, and that if able to, it is their duty to fight for good in whatever capacity possible. Others would see this person as a violent instigator who sees the law only as guidelines to be followed. How can he break these laws and claim to support others?
Essentially, this comes down to ones view of ethics, or what is right. Is right doing good even if laws must be broken, or is right more Socratic, that is assuming the law is right and following it. Confucius believed that laws are put in place for a reason, but as times change, they must as well. Is it then, a question of time and environment that would make this vigilantism appropriate?
What do you think?