Lebanon, along with other states like Jordan, was flooded by Palestinian refugees after 1948 and then the 6 day war and other Arab states sent weapons because syria and Israel considers it a proxy war (after syria got spanked in the YKW).

The lebanese maronite Christians lived on the rich north/sest side (Beirut was once called the Paris of the middle east) while the south/east side (over the mountains) were incredibly poor shia Arab Muslims. The Syrians armed them and told them to attack the west, which they did, and won, which lead to half a decade of civil war that...vaguely settled when Israel invaded and occupied them from 85 to 2000.

Every now and then hezbollah in the south attacks Israel with rockets and such, Israel responds by bombing or even invading, which doesn't really work well for anybody.

It's a disaster that nobody will fix, but it's the same problem as everywhere else, poor rural folk are angry and jealous of rich urban folk who don't care about them and hold them in comtempt for being backwards, we have the same thing in America.

I look forward to being lectured by people who read second-hand propaganda about how this is all bullshit and actually the US specifically did... something that caused decades of war.