It is because "they" want to select to who the land belongs. If you point out that Jews owned property there before 1948, they dismiss it and declare the Arabs/Palastinians were the original owners. If you ask them how the muslim Arabs/Palastinians "acquired" the land, they don't want to admit that mulsims raped, plundered, pillaged and murdered to "acquire" most of the land in the ME. If you mention that Jews lived there since there were Pharohs, they will tell you that is "ancient history" and doesn't count. When I asked for a place where Jews were welcomed and accepted (advertised on a national level), there was total silence. I am so sorry Ropey, it seems many of those that claim to be "tolerant" (of all lifestyles, foreign gods and cultures), have absolutely no tolerance for Christians or Jews. The will eat the fruit of their labor and steal what was produced, but tolerate speech from these two groups, never.
You are missing the fact that its not about the Arabs, it's not about land, it is about, what it has always been about hatred of the Jews. These same people would hate us if there were no Jews in the mid-east, they'll blame Jews for the financial mess, the wars, the this.. The that. It's just irrational, illogical hate thats it. If you seek to understand these types of people you are wasting your time. It is good to know who they are though.