In Israel, Arab and Jews, are living together, working together, studying together and much more.
There are a lot of individuals and families that are in very close relationships with Arab people and trust them for years by inviting them to their homes when they're wives and children alone with them.
So when you lived for years with that trust and suddenly, a few days ago, just because there is a conflict in general between Arab and Jews, one Arab person, damage massively this trust.
He got disappointment with his life for a personal matter, and decided to come one morning to the community he worked with for years, and to shut down people there, causing 3 dead and 1 in fatal condition.
Think what is would have done to your trust in this situation...
https://www.prageru.com/courses/foreign-affairs/does-israel-discriminate-against-arabs