Why is the completely flat Gaza strip a military stronghold from Hamas, while Israel nearly completely controls the mountainous West Bank and there aren't Hamas mountain bunkers and forts there?

Also how did Israel defeat and ethnically cleanse Syrian Sunnis from the mountainous Golan Heights in a few days in 1967 while Palestinians still live in flat Gaza?

Israel btfoed every Syrian Sunni village in the mountains of Golan and only left the Druze and some Alawites there.

I don't understand, aren't mountains supposed to be natural fortresses?