I'm no expert, but I think you have it backwards. My understanding is NIF raison d'etre is weapons research, with a power generation being a secondary concern. It got funded because of weapons research regardless of whether it was relevant to fusion power generation.

It may surprise people, but the DOE is the government body that is responsible for nuclear weapons research in the US.

If it was already decided to be funded, yes it would have been under DoE. Though I believe the weapons aspect had a very major contribution in deciding for it to be funded at all. It was proposed shortly after the nuclear testing ban and has been a big part in fulfilling that area.

I'm not trying to correct you, but adding context for the weapons aspect.