Probably because of the Holocaust. Israelis have a culture where they hate leaving any Israeli behind. They will move mountain and earth to recover a solider.
For his return, Hamas got 1,027 convicted prisoners released whom between them had killed 569 Israeli civilians.
Already one woman released has vowed to become a suicide bomber again. She says it has been her ambition since childhood, and has encouraged dozens of cheering schoolchildren to follow her lead. She almost blew up a hospital last time. She may succeed this time.
I admire Israel’s willingness to leave no one behind. But I wonder if the price they have paid is too high, and if it will result in more deaths. Releasing prisoners is good if part of a peace treaty. Releasing them so they can go out again and try to blow up more hospitals and civilians is not so good.