It doesn't even have to be blackmail...the Ashley Madison database hack/leaks had serious consequences to some involved...once the info is out there, it can't be controlled.
The Data Protection Act states data should not be kept longer than is absolutely necessary. Quite how long Private and R3tro term as 'absolutely necessary' I don't know.
Do excuse the pedantry. I've had a week of working with phrases like 'due diligence'. Whatever, TLC is great and is conveniently close to me.