Cops are some of the greatest "victims" in our society. Encryption will make their investigations more difficult. They'll be judged first by the basis of the race of their suspect and then by the suspected crime. Even bodycams (which they're now quick to hail as they're "recording too," when people record interactions with their phones) were going to impeded their ability to do their jobs.

There are fewer groups with so much power who see themselves as downtrodden. I could name others, but that'd be going off-topic.