I care more about the constitutional rights of citizens to own a firearm than I care about the (relatively minor) consequences of the right to own a gun, sure. Background checks should basically solve the problem. But sooner or later, another shooting will occur and the goal posts will be shifted again.
I'm sure the friends and relatives of the victims will be much comforted with the thought that their loved ones were killed in order to protect the gun nuts right to carry firearms completely unchecked.