I have not logged into Facebook for over a month. Their apps are not on my phone, and I have zero interest in using them.
Today, I received a text from Facebook notifying me that my stepdad posted a photo.
When I logged into Facebook to check my notification settings, I noticed a new section under notification for text messages with all categories turned on. This must me new, and I figure giving Facebook permission to text me for 2-factor authentication must have given them permission to text me about whatever they want.
All notifications are shut off again. I will wait to see if they stay that way.