Defensive wins used to be Worth a lot more, but people exploited it by starting matches with friends then immediately retreating to boost the friend's score. Thus, they changed it so the defender only got a fraction of the Points the attacker lost.
To compensate the change they also increased the Points by 50% - Before the change the max Points available was 50 and an average match was Worth 25 Points, after the change the max Points is 75 and the average match is Worth 38 Points.