There had been no intelligence warning of an attack by any organization on an Israeli target in the U.S., but the way in which the attack took place, its location and timing, seemed to point to terrorism. Unless proved otherwise, that is how the Shin Bet decided to regard it.
Why is it so hard to understand that, just because a lone towel-head isn't a card-carrying Al Qaeda member, he can still be a terrorist. Militant Islam considers every practitioner a soldier in its army. Whether this guy was working with others or not, he was an Islamic terrorist. Israel gets it. Why don't our lame spokespeople?