At some point or another they decided to expand this to include re-engagement garbage like "{{Some person you haven't interacted with in 10 years}} {{ commented on their status || uploaded a photo || added a video}}!", so now I've turned off everything but security alerts.
My current frustration is how they won't let you get notifications about new messages by email. I don't want the app, I don't want to 'delete' my account since we know it doesn't really remove anything and I'd rather retain a semblance of control, but I also don't want to leave the occasional person hanging who tries to contact me via Facebook Messenger, since people can still message you even if you mark yourself 'offline'.
I know this is completely intentional and designed to get me to install the Messenger app and look at their ads, but damn if it doesn't grind my gears. If I could go back to 2005 I never would have made a Facebook account to begin with.
Microsoft/Gates also had trouble with this. What is "business hardball" in a startup, can be illegal conduct in an almost-monopoly.
In a kitten, pouncing aggression is cute... in a liger, not so much. For the same behavior, you'd put it down.
Individuals can similarly fail to recognize transitions. "You can't do X." "But I've been doing X for years!" "Yes, but here you have relationship Y, so X is no longer ethical/legal."
So I feel the GP's pain, I've taken to marking them as spam as well because I know that my settings aren't guaranteed to stay where they are. It's not even in Facebook's best interest to try and keep my notification settings where they are.