This whole thing apparently is caused by OSX and Python3 having no certificates and can't validate SSL connections! This information is sort of hidden away in this itty bitty readme file on the certifi module which then pointed me to the readme file in python3. What. The. Fuck.
There, you'll know that for Python 3.6 on OSX, it requires a post-install step, which installs the certifi package of certificates. This is documented in the ReadMe, which you should find at /Applications/Python\ 3.6/ReadMe.rtf
The ReadMe will have you run this post-install script, which just installs certifi:
/Applications/Python\ 3.6/Install\ Certificates.command
I should read the release notes for Python3 more closely.