Drugs weren't the only items sold there, there were also weapons. If you illegally sell weapons in a country where it is already much easier to legally get a weapon than most other countries, you can be sure that those weapons aren't going to be purchased by a layperson trying to defend themself but by criminals going to use those to harm other people.
The crime being not selling the weapons, but failing to keep appropriate records that ensured the use of the weapons was responsible and that users would be held accountable for their use.
