"From the river to the sea, palestine will be free" implies a desire to see freedom not genocide.
If you're looking for slogans that genuinely impute racist genocidal intent look no further than the Israeli Prime Minister's references to Amalek.
People who say that they support Israel may not believe this imputed genocidal intent is what they support that in a practical sense it is.
To read it literally (and choose one of many possible literal interpretations), doesn't work in this situation, if it ever works. It's not a statement someone just now made up on the spot in an isolated context; it's a slogan in an extremely politicized situation, with many years of history and meaning upon it.
If you want to play join the dots from slogan to genocidal racism, Netanyahu's references to Amalak is what you are looking for.