It is a concern. Every time I stay in Israel, I remind myself that God is in control and protects me. And I was there for both Intifadas and the Lebanon Invasion.
Israel spends tons of effort protecting its people and visitors from Falestinian Arab terrorist attacks. It can’t be perfect but millions of visitors (tourists, academicians, students, merchants, you name it) go to Israel successfully every year.
The Saudi Arabian dictatorial “ruling family” isn’t too keen on hosting a lot of foreign tourists, though there are some (mostly Moslems on pilgrimage to Mecca or traders).The regime has securing agents deployed in all of its major cities, mostly to protect the regime of course but in the process they do suppress a lot of internal terrorism. Visibly- foreign visitors are well advised to stay within the areas under known security. With that said, people come and go with a decent degree of safety.
Not every Arab or Moslem is aggressive, hostile, or prone to terrorism.
I;d visit Jerusalem in a minute! I would have to think long and hard about visiting Riyadh, but would probably take a chance on it if I had any purpose or reason to go there.
Cheer,