Saying "Palestine Will Be Free From the River to the Sea" is a bit like saying "The South Will Be Free from the Mississippi to the Sea".
Come to think of it Palestinianism has more than one thing in common with both "the South will rise again" proponents and native "Ghost Dancers" in the 1890s.
Like those lone Japanese soldiers still fighting World War II on some deserted Pacific islands into the 1960s, post 1865 Confederates, the Plains Indians, and the Palestinians all refused to admit that they were defeated. One might excuse those Imperial Japanese soldiers as nobody had told them that they had lost, but the fact that they had incontrovertibly lost wars has been ignored by the irrational responses of some Southerners, Siberian-Americans, and Palestinians.