Why so many informers and traitors among Palestinians

The news coming out of Gaza is that Israel and the Palestinian resistance movements, Hamas and Islamic Jihad have reached a tentative cease-fire, which should be welcoming news to the people of Gaza, more than any thing else. While understanding the right to fight the occupation, the so called rockets coming out of Gaza are not only useless weapons of war but gives the world the impressions that the Palestinians have an arsenal as powerful as Israel with its F-16s, F-15s. Apache helicopter, 155 mm howitzers, Merkava tanks and Hellfire missiles not to mention smart bombs. These so called rockets are more of an ego thing than a true defensive weapons. The costs of such stupid rockets are so high for all of Palestinians and as I wrote before, is nothing but stupid weapons of war. In any case, I do hope the cease-fire will hold so that Israel stops all of the crimes it is committing on daily basis.
However the subject matter of this article is why and how does Israel manage to target so many people and so accurately, if there was no support on the ground for Israel. By that I mean, so many informers and traitors as if the number of traitors and informers for Israel among Gazans is more than the number of fighters.
Without the support of Palestinian informers on the ground working for Israel day and night, supporting in the killing and murder of hundreds if not thousands of Palestinians, Israel could not fire its missiles so accurately and target specific cars, specific apartments, specific people.
One does understand, that in all wars there are always traitors and informers for the enemy, but the Palestinians exceeded all expectations. Of course one need not only blame the poor people who are forced for one reason or another to become informers, but one has to ask the questions of how Israel is able to penetrate the Palestinian leadership all the way to the late Yaser Arafat and how Israel was able to recruit some of the top echelons of the Palestinian leaderships. It seems that any thing and every thing that happens in Al-Muqata and in almost every home within Palestine Israel knows of it and of course act on it by either killing these suspects or arresting them. Though I do not buy the idea that Arafat was poisoned by Israel, one has to accept the possibility given the number of informers and traitors among the Palestinians and given the strong possibilities those Israeli agents and informers are among top Palestinian leadership.
Without the active support of informers and traitors, Israel could not have the ability of targeting Sheik Ahmed Yasin or Rantisi or know the whereabouts of Bargouthi and could not target specific cars in the middle of the night. Someone must have cooperated with Israel.
In my view that while Palestinians have shown great resilience in their fights against Israel, one has to admit they also cooperated so much with the occupation, to the point that Gaza and the West Bank is becoming like the old East Germany, where every family have an informer among its members.I do not have the answers for all of this, perhaps someone can help