I feel like you're confusing the difference between the legal system allowing it, versus individual landowners consenting to sell. According to traditional Islamic law, the legal system doesn't permit non-Muslims to buy/own land; those Christian Arabs were not advocating a legal system that forbids non-Christians from buying/owning land. Right now in the Palestinian Authority, the law states that Palestinians who sell land to Jews (whether Israeli citizens or not) are executed/killed, and indeed some Muslim Palestinians have been executed/killed precisely because of this law; those Christian Arabs were not advocating such a system. I'm not advocating that Muslim Arabs be forced to sell land or something; what I'm advocating is that if a Jew does manage to buy a parcel of land, that that Jew's Muslim Arab neighbors treat that Jew peacefully as equals, which Muslim Arabs were not doing in the 1800s and which is how this whole conflict got started. If a Muslim Arab landowner wants to sell only to a Muslim, that should be their right (although in America even this would be illegal, but difficult to prove). But the legal system ought to allow selling to everyone regardless of religion, and that landowner who refuses to sell to non-Muslims nevertheless should accept that his Muslim neighbor might sell to a Jew, in which case that Muslim landowner should not engage in violence against his new Jewish neighbor but rather should accept his new Jewish neighbor as an equal.