I could accomplish the same thing by robbing a bank - doesn’t make it the right thing to do.
By that logic, a grocery store giving away everything for free is the right thing to do. Doesn't lead to anything sustainable though.
Actual weapons our government sold to Saudi and other's.
Selling a zero day would probably fall under a weapons clause.
Most zerodays are probably not bought by china to spy on dissidents, they are more like knives. On the contrary, when we sell bombs to Saudis we can be 95% sure they will be used in Yemen.
https://theoutline.com/post/8610/united-states-russia-whatab...