Why would parents stop using the DNA registry if police use it legally? Are parents really saying to themselves "I don't want to provide little 1 month old Timmys DNA, because one day he might rape somebody and I don't want him to be caught"?
Did you not read the article? Some guy was questioned by police for a brutal crime that is only connected to him by the fact that his father's DNA, submitted to a third party and legally fished by police, didn't match DNA recovered from the victim - but was close enough to possibly be a relative. You are a fool if you think that the police only lock up the guilty. I doubt many parents would want to expose their children to the possibility.
I'm curious how you draw the line between what information is okay for them to have, vs what isn't? Why is it bad for them to have your DNA, but not bad for them to have your photo from your drivers license/passport? Is it possibly because you were born and raised in a society where one was common and the other was not?
And what does accountability have to do with this? Whether the government has accress to DNA markers is orthogonal to them being held accountable for their actions
We don't give the government the right to search anyone's house, car, or person without certain cause? Would you be fine if they could because you're not planning to break any laws?
No, but that is different. DNA is something that I literally litter tens of thousands of copies of everywhere I go in public(via skin cells). If DNA is so private, why do we all discard so much everywhere we go?