Well, some people are doing their best to avoid the fact that a Jew killed other human beings in cold blood. I remember when Yitzhak Rabin was assassinated - I was in Israel, on a sherut (shared taxi) going to the airport (at the end of a week-long visit). We heard it on the radio, and one of my fellow Jewish passengers said that it couldn't possibly be a Jew who had done this.
And don't blame Ariel Sharon for this attack. Blame the extremists in the settler movement who have been engaging in the most over-the-top rhetoric possible for inciting someone like this. The people who compare the disengagement from Gaza to the deportations to the death camps create the atmosphere that makes people like this snap. If the disengagement is like sending people to the camps, then anything is justified to stop it. And let us also not forget that the perpetrator was a member of Kach, a banned organization in Israel that has advocated racism against Arabs for many years.
I remember one day in Jerusalem stumbling upon a Kach demonstration in the center of the city. I stood on the outskirts of the (thuggish) crowd to listen to Meir Kahane speak (this was in 1988, I think). He was speaking in the most disgusting way possible about Arabs and how there should be laws forbidding sexual relations between Jews and Arabs - shades of the Nuremberg laws. I left shaking with anger. Let's not pretend that we don't have racists among us.
And let us not forget the plots of the Jewish underground in the early 1980s to blow up the Temple Mount.
Jews, unfortunately like other human beings in this respect, are fully capable of committing terrorist attacks. And just to be clear on how I define terrorist attacks - deliberate attacks on innocent civilians, with the aim of causing death and mayhem, and with the intention of terrifying and intimidating.