Speaking as someone who was very much influenced by what was then the new left, in the 1960s and 70s, I was really struck, on reading Dave Rich's account that I mentioned earlier, how the Palestinian resistance movement has changed over time.
The PLO back then considered themselves a secular, socialist, anti-colonialist, national liberation movement, inspired in part by Frantz Fanon. Hamas and Hezbollah are something very different indeed -- they're populist, antisemitic, Islamists, with views, including violent antisemitism, that I associate with the far right, and which the left would rightly condemn coming from anyone else.
To my mind, too, the only people who're going to make peace are the Israelis and the Palestinians themselves, since they know what they're fighting about, and no one else does, and it's a simple statement of the obvious that neither the Israeli government nor the electorate will accept any settlement that doesn't recognize Israel's right to exist as a Jewish state within more or less its current borders and doesn't guarantee its security (and I don't think any reasonable person, putting themselves in the shoes of an ordinary Israeli, would expect them to agree to anything else).
Quite simply, no set of proposals or demands that don't recognize that reality has any chance of success, and I doubt they're ever made in good faith.