He's most definitely a misguided individual.  But not a vigilante.  He's literally just targeting people he can attack or steal from because he couldn't protect himself as a kid. Therefore he's thinking like a child.

You're right he's using his personal pain to justify attacking people who had nothing to do with him.  If he had of attacked his father that would of made more sense.  

He's lashing out at the world with a child's thought process so hopefully before he gets out of jail they get him some much needed therapy otherwise he's likely to just keep repeating the same behavior when he gets out.

Not sure what made the two women follow him unless they're all drinking from the same cup so to speak