I believe that time lags play a significant role in the Israeli-Palestinian conflict. This works in several ways, firstly each side has a delayed response to the other's intransigence or peace offers. So when Israel withdrew from Gaza, providing an opportunity for progress in peace, the Palestinians responded by electing the Hamas. When Israel withdrew from South-Lebanon, the result was a growth in Hezbullah poiwer and intransigence. The Israelis responded to the Palestinian election and Hezbullah successes by moving to the right, by which time the West-Bank Palestinians - though not Hamas - were in Peace and co-operation mode. So each side is constantly out of sequence with the other. One hopes that at some point we will all be in peace mode at the same time, though the latest opinion poll in Ha'Aretz suggests we're stuck with a right wing government in Israel for at least another election and in the long run we're more likely to both be in war mode.
Another aspect of the time-lag is overseas perceptions of Israel. A generation of European NGO managers (and Israeli leftists) grew up in the Eighties when Israel was invading Lebanon and aggressively settling the West-Bank. Those perceptions persisted when Israel changed tack in the Nineties, contributing to the failure of the Peace process (though many other reasons can also be seen).
Now a new generation of Europeans is emerging that grew up post-al-Qaeda and Hamas, and while the anti-Israelis will no doubt remain vocal, I suspect the new generation will be less willing to criticize Israel.
Time-lag also affects the way criticism of Israel interacts with anti-Semitism: what starts out as event-driven criticism gradually shifts towards an expression of prejudice, due to ignorance and a lack of judgement which in turn leads to a backlash. Perceptions of European prejudice also affect Israeli and Palestinian politics.
Basically people don't change their thinking overnight, there is a time lag, and that has an impact on how things play out. Single incidents/major outbreaks play a role in molding opinions, but I think that over time there is an accumulation of events which leads to subtle shifts in attitudes, rather like ripples going through a pond. Changes may not be total single side-taking shifts, but rather more delicate changes in the willingness to vocalize or support activities.