BTW - The full chant is "From the river to the sea, Palestine will be free." Which entails those in occupied territory and those within Israel.
In contrast there is a strong contingent of Zionists that make a legal claim and title to "all of the lands between the two rivers," The Nile and the Euphrates. Based on he Concept of Greater Israel. This concept is older than the one above.
The entire Palestinian issue cannot be painted with one brush.