My utterly merit-less opinion is: as the amount of kills gets higher, the more valuable your KDR gets, if that makes any sense. Anyone with skill or not can camp to come out on top of random advantageous encounters with the enemy having their back to you, a good 90% of the time and get an end score of like 12-1. On the flip side, it takes a lot more effort (and a lot more skill) to go 36-3.
The reason I see it this way is because going on the offense requires so much more attention and strategy. Runnin' and gunnin' isn't a highly profitable winning strategy unless you've got dead eye aim, blistering reaction time, a good loadout, and superior map knowledge. Otherwise you'll wander into the wrong area at the wrong time and/or get out-gunned when you're running about.