Bit of politics background here.
For reasons unknown to me, the Christians (who are generally Arab, which may be part of the issue) of the area over the years tended to align themselves with the Muslims politically against Israel proper.
There were various reasons for this: social and historical -— and also cowardance and/or idiocy.
Anyway, the Christians let the muzlims in — or flee -— and then things spiral down rapidly.
The same thing occurred/is occurring in Lebanon.
Not suprising since the Arab Christians, and this is the big MISTAKE they have made, thinking that if they side with the Muslims, against Isreal, but in the end, they pay a BIG PRICE for this alliance.