I think another example is required:

A ['Cracker breaks in', 'employee goes rouge', 'a police officer abuses power', ...] and steals all the ['users internet history', 'SMSs', ...] on the system. Which is preferable:

A) Since most of the data has been properly deleted, the thief only has access to the last few days of data to sell or do what they want with.

or

B) Since the government has made it law for the data to be keeped, the thief has the last 6 months to 2 years worth of data to sell or do what they want with.

Which of these do you think will help children get raped?

And I am not even starting on privacy invasion by the government...