That is, of course, correct, which is why I used the term "the people" rather than "me". The role of the police is to protect the collective by enforcing the law, and the need I spoke of exists across that collective.
If he needs a gun for protection, its because he is likely to be in a position where he needs to kill someone.
In that case, he needs a weapon intended for killing -- which would be, as you argue, an automatic weapon. Indeed, if he NEEDS a gun, then he needs the most effective killing machine he can afford.