Apparently the US Department of DefenseWar thinks that they can order non-US citizens not resident in the USA to cease and desist from mailing things.
It's not to stop mailing things. It's to stop mailing things to them. That should be a basic right. I want nothing more than to be able to tell my grocery store to stop mailing me anything, and I'm sure most employers don't want their employees having dildos delivered to their work, especially in places where possession of such items is illegal.
If you're engaged in international business you do actually have to respect the laws of the countries you operate in.