People don't have a "right" to do anything. War makes every action possible; in this case it makes the survival of Israel possible.
And from the other side, I understand why Israel is not particularly concerned about civilian casualties in Lebanon.
http://www.worldpublicopinion.org/p...astnafricara/236.php?nid=&id=&pnt=236&lb=brme
Most Lebanese—including majorities across all major religious groups—support Hezbollah in its conflict with Israel and distrust the United States as a mediator, according to a recent Lebanese poll.
Palestinians also overwhelmingly support both Hezbollah and the Hamas militants who captured an Israeli soldier last month, provoking Israeli attacks on Gaza. Israelis, meanwhile, believe their military should press its attacks against Hezbollah until the militia is either destroyed or pushed back from Lebanon’s southern border.
Eighty-seven percent of the Lebanese back Hezbollah’s response to “Israeli aggression,” the Beirut Center for Research and Information found in survey taken July 24-26. That included strong majorities in Lebanon’s four major religious groups: 96 percent of Shiites, 87 percent of Sunnis, 80 percent of Christians; and 80 percent of Druze