they could absolutely send in a team or assassin to take him out without the collateral damage.
The Rules of Engagement, especially when it comes to civilians, should be adhered to by Israel.
Israel should send their army in to go after Hamas, instead of trying to blow up Hamas by also blowing up the Palestinians via air bombardment.
Political concerns probably keeps that from happening, as when the Israeli body bags of their fallen soldiers start coming back the Israeli public, who are already upset at the current government for allowing this to happen, would be at a fever pitch to remove the Israeli government, and what that would mean for certain individuals who are facing legal issues.