So rights are a privilege now to be dictated by loose wording and interpretation...fuck. that. shit....oh wait...should be old news in light of all the other bullshittery USDOJ spews.
This has always been the case, and it has far more to do with individual state police forces and prosecutors than with the DOJ.
A cop on the street is not spending his time thinking "I want to maximize bad guy X's rights." He is thinking "X is a bad guy, so I want to find out about the crime and throw him away."
All that rights do is they give the cop a script he has to follow if he wants a conviction. If he does not follow the script, or if there is something missing that he needs for the script and he is unwilling to lie, then the case can be thrown out, and bad guy X is on the street. It's like giving a scientist a lab protocol.
So it's far better than not having rights, because (1) it regiments police behavior to some degree (2) it slightly reduces the consequences of abuse of power and (3) you can learn the script and how to use it to minimize harm. But that doesn't mean it makes sense, just that it's a lot better than it is in many places in the world.
Of course, cops lie. That's a part of their job. And juries tend to believe cops more than criminals. Which is stupid but true. So it's a pretty terrible system, but rights can still be useful.