It seems to me that they are simply using an efficient tactic to complete the one objective in the game, which is to kill you. You might not like their way of doing that, but its a legitimate tactic and it works. Thats from someone who tends to avoid using ranged weapons except to try and throw an enemy off balance before closing in, or when seriously injured as a last resort.
If you think thats dishonourable, think of this: I was playing Red Dead Redemption online once, which about seven people all in one part of Mexico. There was one big gunfight going on, so I joined in, and shot the head off some level 30 guy. (I was level four at the time.) Understandably enough, he came back and killed me. I struggled with him for a while, but with better weapons and more practice, he killed me fourteen times in a row. I decided to give up and go find someting else to do. But every time I tried to leave, he shot me in the back. I would usually not even get to my donkey, and when I did I would ride flat out, only for him to chase me and shoot me in the back. I tried hiding, I tried everything to avoid him, but he kept killing me. Once, just as I got to my donkey, someone else killed him, meaning I managed to ride a good distance away, along the train tracks. As soon as he respawned, he completely ignored the guy who shot him, as well as the gunfight that was still going on, chased me all the way to America, and shot me in the back. After he harassed me for 20 minutes and killed me around 40 times, I left the server. At which point he gave my gamercard a bad review lowering my reputation from 5 stars to 3.5 stars. Now that is dishonourable.