The RSS, VHP, Bajrang Dal and such Hindu groups have been banned at several times since Independence in India. Has that stopped them from being active both socially and politically in India? No! If the RSS is banned, the individuals that make up the RSS are still around, all they need to do is regroup under a different name. Same thing with any Militant or Terrorist group. If they are banned, they either go underground and become professional in being hidden terror machines or stay on the surface under a different name. Just like the Jamat-ud-dawa is a front for the LeT.
Prof.Boettke always gives a wonderful analogy about the primacy of institutions and people. It applies here as well. If something were to happen to Microsoft headquarters (such as earth quake etc) that destroys the building completely, does that mean MS will go bust? No! The people of MS will get together in a different building and continue doing what they do best. It is people who drive these organizations, not buildings or names. As long as you have the people the organizations remain albeit under a different name or building.
Here's another real life example about how banning is not effective. The US war on drugs is at least two decades old if not longer. Has that stopped illegal drugs in this country? No! The war on drugs is an ongoing battle into which millions of dollars have been spent, but without as much as a dent in the machine. So does banning have any effect? The sad truth is no. We need to start accepting that terrorists are also intelligent beings, and banning them will not stop them from attacking innocent people.