Google didn't steal. NASA didn't sell the fuel
NASA is a government agency and doesn't have to pay taxes and levies that the private sector does.
The fuel was supplied by DLA-Energy (Defense Logistics Agency), not NASA. The fuel was purchased by H211, a company owned by the top Google people.
DLA-Energy can sell the fuel, but they should collect the tax when they do.
There was confusion because H211 was flying some missions on behalf of NASA, for which they were entitled to tax free fuel.
[The inspector general] 'Martin attributed the discount to a “misunderstanding” between personnel at the airfield and the fuel supplier “rather than intentional misconduct. DLA-Energy misunderstood that H211 was drawing fuel for both private and NASA-related missions.'
Balanced article about the situation: