How much do you want to bet that someone manually goes through to scrub the personal information on every page...any other reasons the white out boxes would be so inconsistent?
This is correct. Redactions are typically handled manually. In the legal industry, for instance, this task is typically assigned to contract attorneys or paralegal staff.
There are of course auto-redacting solutions available, but due to the nature of the documents (scanned, inconsistent formats), and the potential consequences of either mis-applying a redaction or omitting one, manual verification is required.