Given how transparent government spending is and how frequently it’s audited, I think that’s begging the question of how scientific that claim is. The DoD is the only federal agency which hasn’t been able to have a clean audit[1] so it would be reasonable to question them – taking into consideration their unusual size and distribution, of course – but that doesn’t say anything about the rest of the government, or even distinguish between issues with payments vs. things like physical inventory when you have thousands of facilities around the world.

1. https://www.gao.gov/assets/gao-24-106890.pdf