You know who else was shipping firearms illegally to countries in North America? https://en.wikipedia.org/wiki/ATF_gunwalking_scandal

(Obama administration, although not personally his fault)

We could also discuss the provision of Armalite rifles to terrorist groups in the UK, Iran-Contra (an early accountability failure paving the way for pardon abuse), and so on.

The actual reason was lobbying from US companies that were completely losing the competition because of the much lower price for the same or higher quality. But of course, we can try to come up with stories that don't hurt the patriotism ego.