Due to the expansionist racial supremacist nature of zionism the 2 state solution can only come after zionism is defeated.
In that world there is still an israeli population that have a different culture and governmental structure in mind than Palestine does. Are they to be punished for the sins of zionism? Do we support their being ethnically cleansed? Do those people not have a right to self determination? Is the grand plan to have the Israelis subjected to genocide?
A single state solution would breath new life into zionism in the form of an insurgency. It would destroy the Palestinian state.
You can't "undo" settler colonialism. All you can do is listen to the displaced and support what they think is the best path forward.
Maybe 30-50 years of peace after the 2 state solution is implemented things can change to make a single state, if that is what both nations want but you cant just go from israeli zionist state to a single state solution over night. Demanding absolutist "justice" for that undermines the peace process. As a Marxist Leninist we understand that there are stages between where we are and where we would like to be. This is where we differ from Anachists, they demand an absolutist destruction of the state where as Marxist Leninists understand that "the state withers away" after a time of transition under the dictatorship of the proletariat.