It's a favorite rallying cry for gun toters. When I was younger I worked dozens of gun shows as security. The number of FFL dealers in these shows varied but was never more than half the participants. Any transaction done there between a non-FFL gun seller and a private citizen required NO paperwork, not even ID in the state I was in.
The fact is weapons can easily get into the hands of someone intending to carry out a mass shooting. If you're a law abiding American, you should have NOTHING to worry about, and almost nobody holds the view that citizens should be completely disarmed by their government. When Dems are in power the gun lobby hollering they're coming to take them away is the absolute best sales tactic they can deploy.
My interest is to maintain law abiding, mentally stable Americans' gun ownership rights to reasonable firearms for sport or home defense, while also respecting citizens rights to go to a mall, a county music concert, or a child to go to school without getting murdered. The trite calls for thoughts and prayers from the gun lobby's most loyal politicians when these massacres occur are flat out insulting, and the idea that it's an unavoidable consequence of Bubba holding on to his unmitigated right to have guns is worse. Some nutjobs even go as far as to label these mass shootings as staged, fake, agenda-driven propaganda with actors on camera crying for their lost family member. That is the pinnacle of twisted priorities.