yes brit, this is true. I remember the Baader Meinhoff...I was very young when the place where my mother worked was bombed by them.
I suppose, as you said, in free societies there are always those who abuse freedom.
What to do? Well, I think the solution has to be tailor made to aleviate the current problem.
Educate parents, integration,get rid of those who are counterproductive to solving the problem.

Also, make all understand that nothing can be perfect, but we must be united in working towards harmony.