Because nobody has demonstrated working LENR. You can't build that which has not been discovered. Oil wars are effectively fought over energy. LENR would be a significant strategic, political, and economical advantage, and intentionally suppressing it is equivalent to shooting yourself in the foot. America, as one example, could stop participating in an expensive war occurring thousands of kilometers away over an ocean, that is being fought for the sole purpose of stockpiling energy reserves.
We know how to make fission reactors, we have many of them operating right now. We could build more this very second.