A) There are radical Muslims that are prepared to rape a woman who doesn't have a burqa, FGM etc. etc. (One Ex Muslim referred to these as 'Medina Muslims')
B) There are ex- muslims, who don't believe in the religion and help others out. (Also independent people that work with these groups.)
C) There are the majority of Mecca Muslims who do not know much about their religion, Muhammed or the Qur'an.
Stating that Da'esh are 'not really Muslims' is my understanding. A strict reading means they are Muslims.
When some of those Mecca Muslims are faced with abundant criticism of Islam, they are not real fighters or intellectuals so they don't look at Islam and oppose the radicalism, but they do passively oppose it and then they might find someone like Maajid Nawaz (he runs an anti extremism group).
However, the way to defeat this ideology, if that is the correct term, is likely to simply realise it will get better as all other problems do. The problems with the systems today is that the incentives are skewed so that bad deeds are not punished. As things move forward and hopefully into some sort of free market they will be.
As Muslims integrate if they are to they will throw off this ideology, or at least the troublesome behaviours that are connected to it. The funding of Saudi Arabia of Mosques in the West, the halal taxes which are in practice a Jizya. They lose money and this radical Islam ends.
And so here we are! Still waiting on article 50 and the growing nationalist tide against the globalists.
With a full disclosure we will find out the real story behind Muhammed. He was known to wear a turban occasionally perhaps he's one of these large skulled extra terrestrials? This is extremely unlikely though. Since he is not recorded as always wearing a turban and it's the kind of detail that would have been recorded.