RPG makes sense. When you think about it, the roles of police and civilians are completely different.
When a policeman presents a Taser or firearm, most of the time they are trying to apprehend a suspected bad guy. When a civilian presents their firearm, they are trying to survive a life threatening situation. I'm not saying that the police aren't in life threatening situations, it's just that they use their tools differently.
Also, when it comes to a life threatening situation, you want to bring as much force as possible, as quickly as possible. Why? Because you don't want to slow him down or apprehend him, you want to stop the threat right now.