The disconnect was not originally intended as a feature for law enforcement. Most negligent discharges happen during administrative handling. That is, cleaning the gun, etc., wherein the user drops the mag but forgets to clear the chamber, while assuming the gun is "empty". The disconnect was intended to be a safe guard against stupid people doing stupid things. Law enforcement agencies siezed upon that as a security benefit in the case of an officers gun been taken away, but that wasn't the original intent.

Why would they want it removed? For the same reason some prefer a decock only mechanism instead of a decocker/safety combination, because of a perceived liability. The mag disconnect deadlines the trigger. It was felt by some that this could cause a negative outcome if an officer was confronted with further hostility while performing something like a tactical reload. If he needed to fire that one round in the chamber while the magazine was removed, he wouldn't be able to. At the time I thought it was something of a strawman argument to fill out gun rag pages. I really didn't see that fraction of a second where the trigger's dead as a defining moment. It seemed to me that an officer being threatened with his own gun was a much more likely scenario than having to fire off that single round to save ones life. But, some felt differently and specified its removal.

If you're wanting a list of agencies, well, I've slept a time or two since the 80s and I've had greater concerns between then and now. I was living in southern California during the 80s, so a few of those agencies were ones you might know.