The original slogan also was “from the river to the sea Palestine is Islamic/Arab”, but that would be far less catchy in the West.
From where do you get this belief? According to the Wikipedia editors the precise origin is unknown, but a variant matching your claim (except it’s from the water to the water) was coexisting with the “sea”/“free” version (both in Arabic) in the 1980s.
As for equal rights in democratic state, that has to be a joke. Just look at population of Israel where almost 25% is Arabic and compare it to Palestine which is very homogenous.
Why would a Jewish person choose to live in a ghetto rather than Israel. They have innate right to citizenship in the modern wealthy country next door. The people living in Palestine are doing so either because they have a deep attachment to the land or because they don’t have any other choice, not because it’s an attractive place to live. What Israelis have lived there were settlers trying to take land, not integrate into the society. Maybe the Palestinians (which ones?) would implement their own apartheid, but there not being many non-Arabs in Palestine isn’t at all an indication of anything.