Well, powerful entities may not be behind them but it will be hard for India to ban such entities.It is in your own interest because those group is a foreign asset who will try to take over indian government and enslave you.
it is up to india really, but i doubt you can thouch them even if you wished so because they've powerful entities backing them.
You know India is democracy & we can't ban any country or organization just because that revolted against govt...
Well, we couldn't even ban Zakir Naik who uttered nonsense & supported Osama.