Follow the logic. A guy sees a plane, thinks it's a drone, posts a fuzzy video as proof he saw a drone. Others look up, and see lights similar to that first post. Soon, a thousand people have video of "drones" and demand the government act to protect us from this invasion.
Authorities try to calm the public with reason: "The videos are of normal aircraft operating normally." Reason fails.
All the FAA can do is set up zones that will deny LAANC approval in certain places as insurance they aren't accidentally enabling real drones from flying near sensitive place. Used to be you could fly over a dam - they make for good photos. Now you can't. But at least they did something. Yet this doesn't stop all the reports of commercial jets as drones (people can't discern the difference), so the panic continues.
Legislators, whom are subject to the same whims and fancies as the drone reporters, decide to take action. They canvas all the parties who are currently responsible for dealing with the public panic and they all say "YEAH: Let's let Davey LEO figure it out. I'm for that!"
Thus a bill is born.