catholic/protestant sectarianism” doesn’t wash. That is a self-contained problem and one that no longer threatens you and I in any meaningful way.
In contrast, we are in a situation where, if we turned on the news now and ten thousand Londoners had been killed in a chemical or dirty bomb attack, neither of us would be in the remotest bit surprised. In fact, the only thing that would surprise us to the point of it being inconceivable, is if the perpetrators of said attack turned out to not be Jihadists.
See the difference?