Shooter used an assault rifle. Why does anybody need/want an assault rifle?
It wasn't an assault rifle. That is a term of art referring to a select-fire capable battle rifle. Most likely it was some cosmetically-challenged semi-automatic rifle.
Actually, given the press' track-record on accuracy with guns, it was just as likely to be a flintlock musket.
And we don't need them, we are guaranteed them by the Constitution to the United States of America.
Thanks.