Because pk is considering "bad" and karma is the punish.
You could find better way to understand each other before PK. Like change your spot.
Somene weeks ago, i was leveling in cruma 2 with my 2 boxes, When suddenly a party came to my room and tried to "steal it" After 1 hours of "sharing" the room they pked me. I went back and they pked me again. I went back one more time , and they were tooo red than they have to die about 10-11 times. So. I lost about 5-6 % with vip 4, worth?
I think Pk system is needed. Because without it ppl could abuse from other.