You're not describing a vigilante but an Avengers. No on Cap. America, Princess Thor and Hulk but the kind of self focused individuals who view the world only how they are affected. Vigilantes are people who decide to enforce a law which is not being enforced by the government Avengers make their own laws. Sometimes avenging a wrong is justified as righteous behaviour in America. A business rips you off? Dispute the transaction with the mediating credit card company. Someone breaks something you own? File a civil case. Buy a Red Bull, Don't get wings? Join the class action lawsuit and get 10 bucks. Doctor screws you over with bad service or meds? File a complaint against their license. That behaviour adheres to the norms of of culture some of which is leaking into to other societies.
The kind of Avenging you describe does not adhere to the norms of our society though and is considered pathological. They have a perpetual victim mentality due to some hurt that happened in their past or some way they hurt someone in their past which they are not able to face as their responsibility. They also could have just been hit in the head or blood vessel popped causing brain injury. All types are bullies. They may think their actions are for the cause. Foremost in their thoughts is purity, morality and correctness: intellectual purity of the academic institute or webpage, the political and religious purity of the society, racial and physical purity of humanity. They think their support is empathic to the cause and world but really they are just sadistically getting high off someone elses pain. Often sadistic people were abused as children and have love and pain confused on some level. Many murders had bad relationships with their father figures and never learned to be their own parent or the work they did as their own parent was not rational.
In exteme cases these individuals do actual acts of terrorism like Timothy Mcveigh. They have long since aired their grievances generally about one specific topic before they become violent. You'll want to watch Criminal Minds s1e13 Poison for an indepth amount of dramatization on the type.
Creating an artificial intelligence to find individuals who are in danger of becoming violent would be quite easy but the FBI has not seen fit to commision such work.
Originally you asked about antisocial personality disorder or as most people call it sociopathy. This is a citation of DSM 5 describing the disorder numbered 301.7.
A. A pervasive pattern of disregard for and violation of the rights of others, occurring since age 15 years, as indicated by three (or more) of the following:
Failure to conform to social norms with respect to lawful behaviors, as indicated by repeatedly performing acts that are grounds for arrest.
Deceitfulness, as indicated by repeated lying, use of aliases, or conning others for personal profit or pleasure.
Impulsivity or failure to plan ahead.
Irritability and aggressiveness, as indicated by repeated physical fights or assaults.
Reckless disregard for safety of self or others.
Consistent irresponsibility, as indicated by repeated failure to sustain consistent work behavior or honor financial obligations.
Lack of remorse, as indicated by being indifferent to or rationalizing having hurt, mistreated, or stolen from another.
B. The individual is at least age 18 years.
C. There is evidence of conduct disorder with onset before age 15 years.
D. The occurrence of antisocial behavior is not exclusively during the course of schizophrenia or bipolar disorder.
The essential feature of antisocial personality disorder is a pervasive pattern of disregard for, and violation of, the rights of others that begins in childhood or early adolescence and continues into adulthood. This pattern has also been referred to as psychopathy, sociopathy, or dyssocial personality disorder. Because deceit and manipulation are central features of antisocial personality disorder, it may be especially helpful to integrate information acquired from systematic clinical assessment with information collected from collateral sources. For this diagnosis to be given, the individual must be at least age 18 years (Criterion B) and must have had a history of some symptoms of conduct disorder before age 15 years (Criterion C). Conduct disorder involves a repetitive and persistent pattern of behavior in which the basic rights of others or major age-appropriate societal norms or rules are violated. The specific behaviors characteristic of conduct disorder fall into one of four categories: aggression to people and animals, destruction of property, deceitfulness or theft, or serious violation of rules.