First, I think that the further back in time one goes the more likely all parties are to admit unpleasant truths of what their sides did. 
I have only a vague understanding about Syria and Israel and that has to do with the funding of Hezbollah by Syria and the contested Golan Heights.
Where do I go to get accurate background on this?
		
		
	 
The root of conflict in the Middle East is the battle between the herders and the growers; When agriculture first started, the people who grew crops were in constant conflict over land. Herders wanted free access for their animals to roam; growers wanted to fence in their land so that the animals didn't eat or trample the crops. 
Basically there has been fighting in the region ever since. The motivations have changed, but conflict has never gone away, and old grudges have always been as important to the belligerents as their claimed current motivations. 
The conflicts even pre-date (and became enshrined in) the local Abrahamic religions - In Genesis, God takes sides with the meat eating herders, whose burnt offerings are allegedly more pleasing to his nostrils than those of the plant eating growers. The region has a history of old grudges that extends back beyond the beginning of history itself.