Yes, hunters, especially Cat hunters, killed things, and lots of them. Rogues return flags. Druids cap them. Now, obviously anyone can do anything with any class, but some are more suited than others.
Healers and people with only a handful of kills topping the kill charts seems ridiculous to me. Two of them are multiboxers too. Four of them would be if you included the other multiboxers that didn't choose a spec when Pandas reset specs in the armory for people that didn't log in. Kills do not equal skills. Kills are just kills. If it's a kill list, base it on kills. Feel free to add all the other stats too. I think they're interesting, but when multiboxers and healers are topping the kill charts, you know something is wrong.
Like I said, because Cat had so many more HKs per game than Panda, the average is not an accurate way of measuring AFKs. I don't deny that I have more games left than anyone else, everyone knows that, I've probably left a lot more games than that, I leave a lot in the first few minutes. The multiboxing hunter, Genara, never left a game though and your estimated AFKs for them is 1.6k. The reason they have so many estimated AFKs is because they only played during Cat and they farmed every single game, as did I.