Rewarding terror and slaughter with a state and full control of land is not only suicidal, May G-D Almighty protect all, as there would be no checks or balances on what a foreign country could bring in or develop as they plan their next attack, G-D Almighty forbid. It would also embolden and reward terror, and not just in one country, but worldwide.
It would be the same as giving the Nazis some land after WW2 in the hopes that they’d appreciate the “generous offer” and never attack again. It emboldens the worst, with dire consequences, Heaven forfend, for any potential target.