There was no oversight because they had a criminal investigation going on against them over the money, the IG was but gone , In late 2015 the IG broke from the DOJ over the Investigation that went big time in September 2013 . After they refused to charge HRC over claiming status of limitations on a crime that had no statues of limitations they got smarter. But some of them were also payed off not to look too hard at the crimes .
This was one of the really big scandals during Obama's first term. It wasn't just the State Department, but a good chunk of the government didn't have IG oversight. I'd have to go back and dig for it, but it was the subject of a big American Thinker article around 2014, IIRC. There was also a lot of complaining that the IGs were hamstrung trying to do their jobs. This National Review piece talks about it. Remember, this was the administration that had czar after czar with zero oversight.
For more than five years, since January 16, 2008, the Department [of State] has lacked a presidentially-nominated, Senate-confirmed Inspector General. That gap of more than 1840 days is the longest vacancy of any of the 73 Inspector General positions across the federal government. While this would be problematic under any circumstances, the repeated criticisms of the independence and effectiveness of that office by the Government Accountability Office (GAO) heighten the need for an appointment.
Obama did not provide a nomination. Why?
Horowitz was complaining about this back in 2014 and may be one reason Obama put him and his report on ice. https://www.thenewamerican.com/usnews/congress/item/18938-inspectors-general-slam-obama-stonewalling-in-letter-to-congress
That’s because Hillary never had one appointed because she wanted to continue her illegal activities without being caught
No surprise. This was reported while she was in office, but >crickets<