I understand what you are saying and I think that the man himself might well agree. To play Devil’s Advocate here, the reason we can’t allow vigilate justice is that it is subjective, uncontrolled and therefore random. What, for example, if someone killed a person they thought was a sex offender, only for that person to turn out to be innocent, wrongly accused (and even wrongly convicted — it happens). Or what if an individual feels that, say, anyone who does not follow one type of religion should die? Even if they believe it very sincerely, society as a whole has to stop them doing that, doesn’t it?