As a bro who has a family collection of 20+ handguns, rifles, shotguns etc, AND someone who has always had a firearms permit/conceal carry permit, AND has never killed anything with a gun (and don't plan to), I certainly was glad to have a .45ACP under my bed when someone tried to kick in the front door of my home in the middle of the night, setting off the alarm.
This is a tragedy. Innocent children were killed by someone who was obviously twisted and not right in the head. Her guns should have been locked, with the ammo stored separately. Her children should not have had access to the keys to the gun locks or the gun safe.
Do we need guns? Depends on the context. Do we need them to kill innocent people? No. Does it happen? Sadly, yes. However, there are people who legally own guns and have used them in defense of their lives and the lives of their family members...even sometimes to defend the life of a stranger.
It's more important to focus on getting a grip on the black market of guns in the United States and keeping guns out of the hands of those who are intending to do harm, rather than those that own them for sport or self-defense. Furthermore, until we as a nation do more to remove the stigma of mental health awareness and treatment, those in need of help before it is too late unfortunately suffer, and sometimes with consequences far reaching beyond their own family.