This is the thin end of a very dodgy wedge.
I am of course appalled by paedophile crimes, but the knee-jerk vigilante mentality encouraged by this kind of action is highly dangerous.There is no-one quite as dangerous as a self-righteous parent who feels they have the right to harm an individual who (or may not!) represent a threat to their loved ones.
The apropriate response is legal and comprehsnive monitoring, and if that is failing, it needs to be escalated.
Violence from the public is not, and never will be an answer to any situation - however apparently justified the feelings behind such behaviour.
Laws are make us civilised - they should be in place for the protection of every one of us, and we must trust our legal systems and law enforcement to protect us, and address the issues if and when they fail. Simple mob rule will lead to anarchy - the system we have is what we must work with.
As 'Dirty Harry' so memorably advised around thirty years ago - " ... next thing you execute your neighbour because his dog fouls your lawn ..." - that scenario was true then, it;s even more true now.