I believe ComputerGuru was thinking of cyber weapons as discussed in the article. There's very little need to think too hard for examples of the US selling conventional weapons to despotic regimes; and you certainly don't need to go back to the Iran Contra to find the US doing so.

In any case ComputerGuru is rightly distinguishing between stolen leaked weapons versus deliberately selling them. He's not saying that that it hasn't happened, merely that he chosen example was trash.