We do have an Association for Drug Enforcement, but having one government entity cover every bit of gang activity in the nation seems like a lot of effort.

So in Ireland, as mentioned elsewhere, our normal police wear a hi-vis Star Trek uniform, and aren’t generally armed. We also have a few specialised branches for organised crime, terrorism, etc, though; some of those _are_ armed, and have significantly scarier uniforms, and much more extensive training. Same organisation, but totally different role.