IMO guaranteed child welfare (including universal lunch) is 100% consistent with any major political idealogy that is internally consistent.
Libertarianism? The whole basis is the personal choice, autonomy, and the ethics of consent. Children fundamentally cannot consent. They still, however, individual agents. They simply are in a state where social order defines their outcome. As society, we must then take this to maximize their outcomes and ultimately their personal liberty - when they reach an age where they can operate with it.
Therefore, we have to choose between depriving others of a relatively small resource, or depriving children of a major resource: the nature of their ability to participate with full autonomy and personal liberty.
The choice, in my opinion, is very clear.
This is apples to oranges. Fusion is not the same as fission. We simply don’t know the economics of a viable fusion reactor.
However, we do know fissions cost is heavily driven by safety and regulation. It is very reasonable to assume that fusion’s requirements in this area are distinctly smaller.