It literally means for Israel to cease to exist.

Just stating the same lie as a fact won't convince anyone with critical thinking faculties, you know?
The only reply this requires is: "No, it doesn't", and I'm done. You are adequately refuted.

In your first sentence you are claiming that the slogan "from the river to the sea" was made by people that will gladly tell you they want to wipe out Israel. I think you will have a very hard time making this case, but by all means, go ahead.

I'm willing to have my mind changed on this, as I am with all things, because I'm always willing to learn. Are you?