Rabbi Dr. Tzvi Hersh Weinreb of the OU quotes Rabbi Moshe Fuller:

“Some people tell G-d how great their problems are.
I tell my problems how great G-d is.”

What started the conflict in the middle east?
Why has peace not been established between Palestinians and Israelis?
When did all of this start?

Below is a link to an excellent 5-10 minute slideshow by David Horovitz that is super concise, yet highly informative of WHY there is terrorism against Israel today.

I would note that similar answers would apply to “Why is there terrorism in our world in general.”

Although this is not Torah-centered, it is a powerful history lesson.

http://www.terrorismawareness.org/what-really-happened