I don't think that this news is reliable. For long, the ISIS has used this type of gory and graphic videos to recruit psychopaths and mental patients from around the world. If they stop publishing these videos on their Twitter and YouTube accounts, then their recruitment drive will take a severe hit. And right now, they can't afford to do the same.
While they definitely do appeal to many of the mentioned people. One would be naive to think it is true for all, or even most of the people they recruit. Their propaganda has been quite sophisticated and they have shown to be appealing for many otherwise normal young citizens, often feeling like they are not a part of society because of segregation and discrimination. The thought of belonging to cause bigger than their own lives can have a very strong appeal to these people. Most of them will probably find that the reality of this cause is less glorious than they had thought, but often too late.