Personally, I’m rather fond of it (depending on its form), but would consider the situation you’ve described above as someone being meddlesome; IMHO, it’s not vigilantism.
I don’t condone people taking action after the fact; but if, during the commission of a crime, someone wants to protect a victim — and needs to assault or kill an attacker in the process — I don’t have a problem with it. Likewise, I believe that people who shoot criminals who enter their homes are completely justified in doing so.
