You make it sounds as though any officer can buy and use them in any situation, which you know very well isn't the case. This frustrates me to no end!
The police have to spend their time and effort working towards being able to use them, even then, they have restrictions on when they can use them.
The Rebels instead need to spend the time and effort to craft the weapon, once they have it they can use it whenever they want. That's the trade-off.