[jacquesm]

The correlation is simple: A bunch of fanatics has managed to hi-jack a substantial portion of their youths who are vulnerable because of their age and outlook on life nominally sharing the same faith with their handlers who they look up to, and doing their deeds for them (because they're too old, too cynical or too cowardly to do such deeds themselves).

So the correlation is strong but a lack of tolerance will fuel the generation of more of these, not less.