I dont get the ranking system

So far, I understand that whenever you lose a game, you lose XP and when you win you gain XP. You also lose XP when you back out of a game. What I dont understand is the amount of XP you lose or gain. Sometimes I have a decent game with a KD of maybe 1.3 but still lose and my XP goes down by like 15. Then I win a game with a KD of over 3 and only gain 12 XP. Not to mention I get the same amount of XP for going 15 and 1. I just dont like this system that seemingly levels you on team performance rather than individual performance.