Islam is not a cult, it is a meme.
All beliefs are memes.
The various extremist 'cults' of all Islamic sects are offshoots of the original Islam meme that have evolved into their own distinct forms, during the long periods of historical human / meme bio-feedback.
All such beliefs are nothing more than 'memes' which infect human minds and then take control of their host and change its hosts behaviour / culture rather as Toxoplasmosis does with cats, rats and humans ;
As a meme the various sects of Islam, like all such memes, have their own distinct pathology.
As with all memes, if one wishes to 'kill' it, then you must target those infected with the meme and also those who are transmitting it. At the same time you must 'jam' its transmission into the wider community.
That means moderate Muslims must speak out loudly and constantly condemn Islamists of all sects and work to keep extremist sects from spreading into their communities.
This prevents the spread of the progenitors of rogue memes like Wahhabism and Deobanidismn that assist in the spawning of ever more extremist memes such as Al Qaeda and the Taliban spreading into a community and infecting new individuals.
This is why you see Deobandi Shiites in Pakistan attacking Sufi's.
It is a war of memes, played out by their meat puppets.
At the same time as moderate Islam speaks out and condemns the extremists, the state must hunt down and deal with the extremists and the promoters of extremism.
Neither requirements are being undertaken at sufficient levels at the moment.