On the basis that competition would actually bring something to the game? While the game is highly deficient in a real way to have competition with other players, that not the goal of the game. Since this game is co-op it would similarly counterproductive to think that anyone would play better if stats were being tracked. It just gives the people who are really bored with the game and only want to watch numbers increase something to do. Personally I would like to have stats available because it is interesting to see what you total specs killed, accuracy, and what not, but I would rather it not be introduced on the basis that it would seem to direct the game in a path I would rather not see it take.
NOTE: This applies to both server and global stats
There's 2 types of people there, and one of the two is fewer than the other.
Type 1 : The one that cares.
Type 2 : The one that doesn't care.
For example, when I used to play this MMORPG with rankings, there was some guy at lvl 150, with billions of experience. I would never come that close to him, so I didn't even try. I played normally.
No one's going to complain. It's going to be the same as it was, but we can actually see our progress this time.
The only time your argument will apply, is if for example, we get an award at the end of the game for most kills.
Which will does not apply at all to my suggestion.
Also, on a side note, If you're the guy that has the most kills, and there's the other people with half the amount of kills you have, that just indicates they aren't trying, and not putting in team effort. I'm sure they wouldn't cry that they're sucking.