Well-trained thugs with the firepower to shoot their way past a poorly armed police force. Its a shame, Dupree, that you can't go along with your local cops when they go on a drug raid, or a high-risk felony warrant attempt, or a shooting call, or a domestic disturbance in which shots have been fired. I wonder if your feelings would change after being first man in the door on a few high risk entries. I bet it would. And I can guarantee that you would never work as a cop after that without wearing a vest.
Cops go places others flee from.
A cop who doesn't wear a vest is asking to leave his wife a widow, and there are plenty of people willing to make him one. As to your ludicrous claims about the MP5, those weapons are typically reserved for the highly trained officers of the Emergency Response or Special Weapons and Tactics teams. While individual officers may own these weapons on their own, very few departments have authorized regular personnel to carry them in their vehicles, and even then they are restricted to extreme emergencies for their use. There probably are some out there, but those agencies are by far the exception. The Barrett is impractical for many law enforcement scenarios due to its over-penetration.