If Grandma were running around distributing fliers with the kids' photos on them, there'd be no controversy—that's weird, and of course the parents can ask her to stop, and if they ask, she should, and it was kinda crazy to do it in the first place.

Posting them on Facebook is exactly that but 1,000x worse, but it's "normal" so we have a debate about whether it's right for them to ask her to stop.