From my time in fusion research circles, you're correct, but it's also not a simple "weapons or energy?" question. It could only have ever been a pure research facility. At the time of design, the physics wasn't certain enough to aim for net energy gain. Where the weapons research came in is in the choice of laser focus. Instead of "direct drive", where the lasers directly strike the fusion fuel, NIF lasers strike the inside of a Hohlraum, which produces X-Rays that then heat the fuel. X-Ray opacity is an important topic in nuclear weapons research.

Bear in mind that I wasn't directly involved, and this my impression picked up from conversations during my time in fusion research, which was about 10 years ago.