With humans, it's more about control then actual possession. They'll let you own whatever you want, so long as they retain control over it.
Zionism is all about control, ... and ownership ... by Jews only.
Even if that was the case (and I'm not saying it is), they only seem to want to control a tiny sliver of land.
But it is a human problem. I've seen the pictures and read the stories about the conditions the Palestinians are facing in Gaza and the West Bank, and I would not defend the actions of the Israeli government any more than I would defend the U.S. government under similar circumstances.
But it seems that a lot of people are suffering and living in pretty crappy conditions and need assistance. It's pretty sad and disheartening, and it gives one a feeling of powerlessness, whenever one sees situations where people are in these dismal, hopeless positions. For much of my life, for decades, I've seen the news about all the various peace talks and conferences and discussions about what to do about the Israeli-Palestinian problem and the larger issue about peace in the Middle East. But there's never any real lasting peace, just occasional lulls in the fighting.
As for the West, we supply the lawyers, guns, and money. Our own governments are not entirely innocent bystanders here, as we've been meddling as well. I can sort of understand that these Berkeley students might be motivated by the overall cause of global justice and human rights - which I also support. But in targeting the various sources of global injustice, the question still remains, is Zionism a valid target, in and of itself? Does Zionism cause injustice, or is it just certain right-wing politicians, both in Israel and the US?