First we need to understand that TLP is not only a political party, it is a mindset, which has been groomed over a period of decades in Pakistan and has been used and misused by many in the power game (including establishment).
Use of coercive power to curb these menaces is only a short term relief, like a painkiller pill, which only subsides the feelings of pain, while not doing anything to the problem from which the pain emanates.
Suppressing such factions by the use of brute force will do more harm than good. Remember, their sympathizers are also a part of this government and bureaucracy. Just like after Laal Mosque fiasco, there were more insider attacks on Pakistan Army than from the outsiders.
This is a mindset, which needs to be mollified and then reshaped. This cannot be done through use of force. They are very likely to recoil when the time is right. Rather, use patience and give them a face saving to retreat. Then reshape the minds of general public on this issue through media, debates and curriculum etc.