Fleet Foot user: gunfighter.
G-MAL user: hard to come up with just one word. Ideally, it'd be "person who wants to pick off enemies from a greater distance".
ROF M9 user: scrub.
Notice I didn't use the word that somebody else used to describe Fleet Foot users in my signature.
Here's a better question:
In one word, how would you describe all of the whiny cry-babies in this game who want everything nerfed until the point where the game becomes a mindless run-and-gun fest where nobody has to think and strategy and variety of playstyles becomes irrelevant?
This community is so emabrrassing. Nobody likes a challenge, and everyone wants their kills handed to them on a silver platter.
And for the record, let me state that I use neither FF or ROF for the M9.