Because Israel loves murder:
1981: Bombed Iraqi power station killing 2 Iraqis and one French citizen
1982: Attacked and invaded Lebanon. 25,000+ Syrians and Palestinians killed
2003: Military incursion into Gaza and Nablus
2006: Attacked and invaded Lebanon, killed over 1,000 men, women and children.
2007: Attacked and bombed Syria
2008: February attack on Gaza, over 100 murdered.
2008: November attack on Gaza, killing over 1,300 civilians, and then refused to co-operate with UN investigations
2010: 9 murdered in attack on aid flotilla in international waters.
(before 1981 there's much more, like their sinking the U.S. S Liberty but it's just too long to list all their attacks :)