Israel captured this territory because of war, and offered to return it for peace. So far the Palestinian leadership has not offered peace, only more war. But that doesn't stop people like you from asking Israel to give up the land anyway.
Why should Israel give up the only thing she has to trade for peace in exchange for nothing? It makes no sense. It would be stupid for Israel to give away her only bargaining chip for nothing in return.
It makes no sense at all to reward terrorism. It makes no sense to surrender and acquiesce to the losers in war. This kind of attitute only encourages more terrorism and more war.
Do you suppose that's what they want?