Because when they say it, the mean Isreal from the river to the sea. It’s the reverse (and not any better).
It’s the reverse (and not any better).
When you think about it, settler colonialists and native people are just two sides of the same coin.
from the river to the sea / Palestine will be free
and
Between the sea and the Jordan there will only be Israeli sovereignty
Carry the exact same connotations and historical weight.