It isn't. Israel isn't getting any prisoners back. They are getting dead bodies. Calling it a prisoner exchange implies that there is an evenness to this deal - that each side is getting something equal. Not true.

This is both a gesture by Israel, and a way of demonstrating their moral superiority to a group like Hezbollah, which has no regard for individual life. There's plenty to criticize Israel for, but this non-exchange is a good reminder of the moral imbalance between the Israeli population and some of it's more fanatically religious antagonists.