Compared to a 25:1 loss ratio, 3:1 is a big improvement
I think that's the point the author was making. The suicide bomber tactic is much more effective at killing Israelis than the previous tactic of having kids throw rocks at armed troops. Suffering 3 deaths for every Israeli death is indeed better than the previous rate of 25:1. Funny how you overlooked the obvious.
One other point - if the person is shooting at you or getting ready to detonate a bomb, he/she is a combatant regardless of whether or not he/she happens to be in the military. That person is not a true civilian. Combatants are legitimate targets on any battlefield.