>> I honestly have not a single idea why there wasn't this type of department before monitoring and auditing everything.

You mean like the Government Accountability Office? [1] Or the dozens of Inspector Generals at most agencies? [2]

[1] https://www.gao.gov/

[2] https://www.oversight.gov/where-report-fraud-waste-abuse-or-...

The US federal government has lots of laws, agencies, and procedures to address, investigate, and remediate fraud, waste, and abuse.

Because then they would have found the fraud, and some very powerful people would be out of money....