I hadn't realized that there had been additional posts to this, but to respond to My Cat is a Ninja, I left a comment to the Admin's post in the small admin group about reinstating Stalker. I commented, "As a matter of principle, I cannot stay in a group that condones a stalker. I'm out of here."
Thankfully, my FB has been very quiet since I left those groups, so perhaps I've avoided their usual drama when someone has fallen out with them.