Most people don't actually know what DOE is. For starters, it's officially one of the 17 USG intelligence agencies.
It houses the national nuclear security administration which is responsible for military reactors, nuclear weapons, and nonproliferation.
It operates the DOE Science and NNSA Weapons national lab and site complexes via M&O contracts (of which Bechtel is one of the longest contract holders).
NNSA is congressionally funded via energy and water, but it's authorization is via the armed service committee National Defense Authorization Act (same as the military).
None of this is a nefarious secret, and all of this and quite a bit more can be found via the agencies website.
Folks completely misunderstanding what government does. Forget about DOE, how many folks actually understand what HHS does, or HUD, or any of the dozens of other agencies other than Defense and State.
The USG is full of these enormous and powerful bureaucratic orgs. Not surprised that most folks (including me!) Are unaware of what our tax dollars fund, but boy is it a lesson in complex systems.