gavra_at_work,
I don’t buy the “He was not normal” argument.
I have not read much about the incident, but the details I have read seem to point towards mental instability. That steeping in the seething nastiness of the Israeli political climate may have provided a focus or justification for his actions in his mind is a good question. Where a “normal” but misguided person may vilify, an unstable person may act violently. He probably did view himself as upholding some sort of religious honor, but I don’t think his thought processes were rational as you suggest with your question.