My guess is the police and law enforcement fully understand how these databases are abused and often for personal reasons. Hence, the desire for privacy. This could be a real problem is there is a bad apple in the ranks who is shielded from his crimes by the exclusion of his DNA.
To shield them or set them aside from the society they are members of is a dangerous precedent. A precedent that sets them up as a praetorian guard of sorts. For the full article see Police cite privacy concerns over their own DNA
Speaking of creating an elite Praetorian Guard that is above reproach and apart from the normal checks of society is a recent initiative of the DOJ to make it a crime to satirize the excesses of the TSA agents in our transportation centers. It is satire that can be a non-confrontational check on the actions of agents by society.
“In the past, satire was protected under the First Amendment, but it may soon be illegal to poke fun at the TSA or use its logo or even utter its name. Notice there is no exception in the above language for parody.
Political satire is as old as the Greeks and the Bible. But it may now become a punishable crime if this legislation is enacted.
The TSA and the Justice Department are obviously serious about making sure we don’t criticize their Gestapo operation. Since they began irradiating citizens with naked body scanners and shoving their hands down the pants of old ladies and grade school kids, public outrage has reached a crescendo.”
Md. TSA Agent Charged With Child Porn
TSA Pats Down Breast Cancer Survivor Even After Getting Scanned