Ah, carbines. Been using nothing but SMGs lately. I fondly remember the days when I could reliably kill targets beyond 20m...
You probably should have cut that little tell spat with the infiltrator. Neither one of you come off well.
I used to think so too, but when I actually started using them, they weren't so terrible. They are somewhat not versatile, but over the time you just learn to control your distance. Of course, there are times when an enemy catches you unguarded, and you don't have anywhere to run, and it's too far to engage him. Those situations suck, but they don't happen that often. Using a more versatile SMG, like NS-7 or MKV also helps in that regard. They don't do that much damage up close, but you can dig yourself out of that by going for headshots, which isn't always easy, but at least weapons themselves make it as easy as it can be.