> they should have oversight

Congress provides oversight and accountability of the Fed. The GAO does audits as well. Frank-Dodd provides more windows into the Fed. Why did you think the Fed doesn't have oversight?

> Not ever passing an audit of any kind

It might have been hard for you to find because it is hidden under the "audit" page on their website: https://www.federalreserve.gov/regreform/audit.htm

> Why is the independence of the Federal Reserve sacrosanct?

It's never been completely independent. It's independent from short-term (4 years) political influence. It's audited and has congressional oversight and the President nominates people to the board.

What else do you want? Interest rates set by Presidential tweets?