Car registrations are required. You are allowed a choice of owning a vehicle knowing what it requires. Sample of your DNA and fingerprints is not a requirement when we are born.
Thus I find the comparison not adequate.
With GDPR, you should be able to force 23andme to delete your DNA information after you received the results. That's if you're European at least.
I see no issues with this chain of investigation. Some tools the police have access to you cannot personally opt out of. That's working as intended.