When they chant "from the river to the sea Palestine will be free", what do you think they want? Israel is located between said river and sea, so they want to exterminate all Israeli so the land is all theirs. The extermination of all Jews is codified in written form in the Hamas Constitution.
If there are people there who only want to advocate for the Two State Solution for Israel/Palestine, that's a fair point to make. But when these people, knowingly or unknowingly, mix themselves with people that carry Hamas flags and chant "from the river to the sea", then they're either useful idiots, or they're pro-Hamas while using the pro-Palestine cause as a cop out.