Yes, they also all consumed mothers milk.
Being radicalized is code for 'impressionable person ends up believing stories by some fraudster'.
Let's cut to the chase here, this is why we won't be solving this any time soon:
Religion pre-selects - in all its forms - the gullible, those, who would rather believe a story than the evidence before their eyes. Because of that and that alone we're stuck with this problem because our societies would have to outlaw all religion as some kind of disease if they're going to gather up the tools to do something about this problem on a scale where it will make a difference and within the framework of our legal systems, that is, without prejudice against one religion or another.
But of course that will never fly, it would create a huge immediate problem, much larger than the one posed by terrorism. It would require all those that are involved in some other religion besides Islam to come to terms with their own religion and this will - given the influence of all those other religions, particularly Christianity in all its forms - never ever happen. And if it did it would make the current crop of terrorists look like rank amateurs.
See also Richard Dawkins' 'crusade' against religion in all its forms, even atheists are not immune to telling others how they should live.
If you're going to find one common element between Crusaders, IRA/Unionist bombers and Islamists (and a whole raft of others besides) it is a categorical in-ability to keep their religions where they should be: in their houses and their places of worship.
As soon as people go out into the real world and start telling others how they should live it's game over. So, as far as I can see we're stuck with this problem for the foreseeable future, until enough blood has been shed that people will come to their senses again. It never was any different.