Because it's not chock full of American-hating Hezbollah terrorists.
As someone who has travelled several times to the country in recent years (it was a favorite spot for R & R from Iraq), I can assure you that Beirut is easily the loveliest and most tolerant city in the Middle East. Stroll along the Corniche, eat and drink in the fabuluous bars and restaurants in Achrafiye, watch the hot babes in tiny skirts wander down Bliss Street, soak up the sun in the beach clubs on the Med or ski in the mountains, and you will swiftly realise this is not an Arab city.
Most of the country is fine to travel to as well, Baalbek and Biblos are truly superb and even Tyre and Sidon have their charms.
Hizbollah extremists are in the south and continue to receive backing from Syria but let us not tarnish the wonderful people of Lebanon with the same brush. Remember Lebanon was OCCUPIED by Syria till recently until the Cedar Revolution in 2004 which was hailed as a positive consequence of the War in Iraq.
Israel's actions against Hizbollah are justified, but spare an thought for the many innocent people of Lebanon who are facing tragedy at a time when hope was at its highest after so many decades of catastrophe. The tourist industry will be dead from this and many innocent lives shattered. I am not attacking Israel, but we need to face up to this reality.
We also need to remember that most of the Lebanese government hates Hizbollah as much as Israel does. The problem was their weakness made disarmament all but impossible. The Lebanese government needed far more international support than it did and to a large extent we have let them down.
Lebanon let their country become a rat's nest. It's not Israel's fault. The Lebanese people are not innocent victims. They did this to themselves.