Why have the protests in the North taken an unusual intensity?

Attacking the Jaffna Court Complex and the hartals which have been in progress yesterday and today in the Northern Province and some districts in the Eastern Province are claimed to have been to pressurize the authorities to take strict actions against the perpetrators who ganged raped and killed a teenage school girl in Jaffna.  

Staging protests demanding justice being delivered is a right of the people in a democratic society. But why is it in such a violent manner and massive scale going to the extent of attacking courts and launching widespread total hartals making day today affairs of people standstill? Why don't we find these types of strong, widespread and highhanded protests in other parts of the country despite the type of heinous crimes such as the one in question are reported many times frequently in those parts?      

Do these protest coincidence with the total elimination of LTTE terrorism from the shores of Sri Lanka exactly 06 years back of which remembrance of the dead took place the day before yesterday? These actions have eerily resemblance to the manner in which Tamil militancy led by LTTE was launched in late 70s and early 80s.