Bots can bypass privacy settings.

The ability for a bot to bypass privacy settings created by users.

Or perhaps a "bots can message me" privacy setting to give the users the option to allow bots to message them.

I've come across this issue multiple times since my privacy is set by default to not allow non-friends to message me and servers sometimes use bots to send DMs to users upon joining. I'm aware that just letting bots send messages willy nilly could be problematic since some people design bots specifically to spam users, but there needs to be some sort of work around to this.