I think the point is that 60 Minutes has a leftist political agenda and has had one for a long while. I've been watching the show longer than you have been alive. This is not a general investigatory piece but a segment designed to worry people about AR-15s and motivate them to support a political position. They editorialize by virtue of what they select to cover and how they cover it. Notice that the segment did not contain any accounts of people who defended themselves against multiple home invaders even though such events have occurred.
You won't see 60 Minutes doing a story about how the elimination of most bail in NY has resulted in many arrested criminals being released without bail, and then going on to commit further crimes because it does not further their political agenda, nor the politicians who they support--like NY Governor Andrew Cuomo who spearheaded the elimination of cash bail in NY State.