If ISIS soldiers were so loyal why would they pay a wage?
They use a combination of scare tactics and finance to keep many of their soldiers in the fight.
Of course there is a hardcore majority, who fit the broad sweeping brushstroke you applied.
But I think its abhorrent for you to suggest that Islam and the Quran is to blame for the actions of these monsterous individuals. I think it is incredibly reductionist and driven by an all too familiar agenda of modern times, an innacurate belief that secularism automatically equals progress.
Their religion is not the sole reason they are doing this, it is a far larger issue. Which can be directly linked back to factors like: Western Colonialism, Gulf Geo-politics and American foreign policy. Their interpretation of Islam is a small factor in the grand picture. It of course is a factor. But don't let that stop you from peddling the same argument in every Current Events thread which essentially is... 'religion is bad m'kay'.