Israel's point of view is far more simple. In contrast with the Lebanese society, Israel is far more homogeneous. Which is due to many factors.
On one hand Israelis have alot of common enemies. The Lebanese have alot of enemies, for each sect an enemy or two.
Israel is economically stable and relatively prosper. Lebanon's struggling to survive the debts which puts alot of pressure on the central authority and fortifies the seperatists.
Israelis have in fact one religion, even though there are many Muslims and some Druze, Israel is the Jews' homeland and serves only there interests. Lebanon has too many religions and each claims to BE Lebanon, not to mention that (almost) each sect serves the interests of some external force.
Israel has won practically every war it has launched or resisted. Lebanon... Well let's just say that Lebanese are simply too tired of war and too tired of thinking about it to the point where we'd prefer leaving our country on fighting for it anymore.
So in general the Israeli position is much more at ease. They had been preparing for a long time now a massive military operation on Lebanon. I mean, last time I checked Israel was always one step ahead of Hezbollah, it was always protected and the Israeli soldiers are much protected. I doubt that it was enough for Hezbollah to simply enter Israel take a couple of soldiers and then retreat back. Not just that! Israel had already lost one soldier for the Palestinians in Ghazza! I doubt that the Northern borders would even be relaxed enough to allow ANY Hezbollah movement! In my humble opinion, Israel wanted these two Kidnaps to take place, to put into action its military assault.
What ever it was, Isreal played its cards well (as always). Not only they made sure to give the international and Israeli public opinion good justifications for the assault and they did there assault in a very smart and effective manor. According to the latest statistics (on Tuesday) almost 70% of the Israelis are totally behind there government, anything higher than this percentage indicates fraud and/or dictatorship. In addition, Israel has an international support, not to mention the American traditional Veto support.
So for at least for now, Israel has no reason to stop.