Trying to put words in the mouths of protestors, doesn't work. But also, at least look up what a slogan means before you chant along lol. Self explanatory it is not in this day.
Asking Palestine Protestors What From the River to the Sea Means...
Too many people can only think in binary terms, with us or against us, Israel or Palestine. With that outlook on life there will never be peace. There are plenty things that are binary, murder, kidnapping and genocide for example, as well as occupation, apartheid and racism. Yet Judaism, Christianity, Islam are not one good rest bad. Even Zionism had good ideas at the start, yet has been abused and transformed into facist colonialism.
Comparing what the slogan means between Likud party charter
"The original 1977 party platform stated that "between the Sea and the Jordan there will only be Israeli sovereignty." The 1999 Likud Party platform emphasized the right of settlement: The Jewish communities in Judea, Samaria, and Gaza are the realization of Zionist values."
And the 2017 Hamas party charter: the 2017 document stated that Hamas' fight was not with Jews as such because of their religion but with the Zionist project. However, Hamas fell short of repudiating the original, 1988 charter, saying it was a document of its time and the new document represented Hamas's position for now.
https://www.wilsoncenter.org/article/doctrine-hamas
Anyway even the old 1988 charter is against the Zionist project, the one stated in the Likud party charter in 1977. Typical Israeli projection.