This is very bad, the coast guards should return them back to their respective governments instead of dragging them right back into the ocean where they might run out of fuel or food and die on the way. There must be some stricter measure to monitor and take care of this issue as many people are dying time after time.
It is not that simple. Most of these migrants are from distant nations such as Ghana, Nigeria and Liberia. Once they get to Libya, they will destroy their passports and other identification documents. This is done to prevent deportation to their home nations. Now the only option is to send them back to Libya. Before the NATO invasion of Libya, that was being done, at a limited level. But after the NATO invasion, this option is not available anymore.