Ok how's this? Every (almost every?) mass-casualty attack inside Israel borders in the last say, almost 70 years, have come from ethnically/religiously similar people. These attacks happen at an alarming rate. You would like them to, for the sake of making you feel warm and fuzzier on the inside, not profile the people most likely to carry out such attacks in the future? That would be ridiculous.

Edit: before I get downvoted into oblivion, and I'm sure I might, I'd like to add that reality is almost always uglier than anyone - especially me - would like it to be.