Yep, I agree. But in the case of this MI school massacre, since the gun was the murderer's own weapon, given to him a few days before by his parents as an early Christmas present, a safety lock wouldn't have made any difference.
His parents raised a monster, just as Madison Cawthorn asked them to.
Madison Cawthorn: "Be armed. Be dangerous." "If you are raising a young man, raise him to be a monster."