Then the Israelis guarantee their future in a perpetual slaughterhouse.

Well, from talking to my family members over there, they pretty much believe that's the case with either path.

Opposition to Palestinian sovereignty is now based on the firm belief that there will always be a sizable proportion of the population (the Hamas faction, for now) that wants a "one state solution" - the expulsion of the Jews. Because there will always be geopolitical actors that want Israel to be bogged down in war and strife (formerly the USSR, now mostly Iran), this faction will always have sufficient resources to control any sovereign Palestinian state. Even though the majority of Palestinians would be perfectly content with peaceful coexistence, they can't stop the minority from wrecking it. That there will never be a sovereign Palestinian state that is capable of stopping Hamas (or its successor) from seizing power.

In other words, the "guarantee" is that you eventually end up with the same situation you have now - Hamas running things and attacking Israel at every opportunity - except now there's the real possibility that they'll have an army and an air force and borders that they control.

Since the opportunity for a stable partition has passed (if it ever existed), they're resigned to continued conflict. They'll therefore choose the future of conflict that they believe results in the lesser security threat to Israel, which is to oppose Palestinian sovereignty.