Take into account the players that don't play much crucible and just give up a ton of kills, then don't play again. Their deaths are recorded into the overall KDR but are never made up in the long run. Meanwhile a player that does well in crucible will continue to play crucible and add many more kills into the equation than deaths. Since the former type of player is likely to be more numerous than the latter, the median KDR is driven downwards. I would want to see the KDR at the 75th percentile, the 50th percentile (median), and the 25th percentile. I would bet it would be 1.1, 0.8, 0.4 respectively.

That person that plays only 1 game, and goes 1 and 10 still has a kd. It's .1, and that .1 counts just as much toward the average kd as a person with 1000 kills and 1000000 deaths. They both have a .1 and that .1 counts just as much as the guy that played 1 game and went 8 and 1. Average kd is your kd plus my kd divided by 2. It works like that regardless of the number of players and regardless of the number of kills a person has. Because we're using averages... An average of averages.. Its simple. There's a difference between the total kd and the average kd globally.