Forensic analyst here :)
Genuinely the vast majority of cops don't. And indeed IMO sending this sort of thing off to contractors is the necessary sort of separation to make sure that dirty cops can't incriminate you.
So on one hand I defend my profession; which I have always found to be supremely ethical and approach cases from the perspective of innocence.
And on the other hand I entirely agree; this move removes an important separation of evidence retrieval that means it could well be abused.
As told to me by some friendly police officers I would chat with.
"An law school professor and former criminal defense attorney tells you why you should never agree to be interviewed by the police."
PS: this does nothing against phone numbers and text messages stored on your SIM (the vast majority of smartphones no longer do this, AFAIK)