Let me play devil's advocate here, I've known a number of law enforcement/military individuals and have asked them the same question. Here's the situation they paint to me. Imagine you have to go arrest someone, essentially using force to limit their freedom. You know virtually nothing about this person, except that they are the type of person who will break laws serious enough to get arrested. Now, do you want some protection from a gun, or no? And do you want to go there with 1 other person? Or as many as you can get.

It seems very excessive from the outside, because we have full knowledge of the situation at the outcome. When you go into these situations, you're essentially blind, so you're exposing yourself to the entire risk profile.