That policy was not in force when you did the job, so it's quite likely had the incident happened on your watch it would have been dropped.
A number of countries have moved in this direction in recent years for DV cases if the responding officers have seen evidence of it. The repeat nature of DVs where the offending partner knows that it will not be followed thru in the past, the victim being dependent, fear etc are probably factors in the change in direction. So no fault of CPS as they cannot be seen to be selective. Seen enough in my neighbourhood during my formative years to understand the change.