As a dude who's played a couple of shooter-type multiplayer games for many years, I'm sort of confused as to why most people who play LD seem to place so much stock in their damage dealt per match, or even why it's a recorded stat in the first place. I mean, the name of the game is a control-points style competition, so at the basic level, the amount of times you capture or defend a point is what actually contributes to your team winning. The main way to do that is obviously by making your opponent deader than you, so if you're racking up kills, odds are you're being a good teammate. But what does damage show? Picture a scenario where you keep hitting a certain player a few times, they run off to base to heal up, they come at you again, you deal more damage, repeat. You could rack up a huge amount of damage on that person, but you wouldn't have killed them once, and you might not have had much of an impact on the overall match. But going by the usual standards, you could be viewed as having an amazing round.
So yeah, color me confused why the damage dealt in a match is supposed to mean anything, while your kill/death totals, which are kind of the basic metric of every PvP combat game ever, don't even show up. :P
The same reason why COD players care about their K/D ratio even not playing a DM.
Having more damage than other try makes themselves better than the others of trying to prove they were the "soul" of the party.