The article glosses over it a bit, but I think it’s important to stress here that this isn’t energy gain in any real sense. Its more energy being created from fusion than laser energy gets to the target, but before then 99% of the energy input is lost in creating the laser beams.
So to give one of the examples used in the article, 2MJ of laser energy is delivered to the target and 3.9MJ is released. But to create this 200MJ was consumed to create that laser pulse.