Facebook is an environment with confusing boundaries. It’s easy to inadvertently cross lines on Facebook. Almost everyone ends up inadvertently violating boundaries on Facebook that they would never violate in person.
But not all boundary violation on Facebook are like that. Facebook can also be used for stalking. Serious stalking. Not semi-cute awkwardness like commenting on too many things.
Facebook can be used to harass people. It can be used to try to force contact. It can be used to track someone’s movements. It can be used to find out who the victim associates with, and then to try to use those people to get to them.
If you are Facebook friends with both an abuser and their victim, this can hurt the victim. It can, and often does, result in you accidentally giving information to the abuser that it is dangerous to the victim to have. This is the case even if the victim has blocked the abuser.
(For instance, photos of the victim that you post or comment on can show up in the abuser’s news feed.)
If you’re close to someone who is extracting themself from an abusive relationship, and they ask you to unfriend their abuser, it’s important to take that request seriously.
This is serious and a huge reason why I deactivated my facebook. Mutual “friends" - who I foolishly actually believed were my friends - used my fb profile to find out what events I was planning to attend on the weekend and then would tell my ex-boyfriend so he could show up and harass me. Then I had other friends who were not close with my ex and no longer spoke to him, yet they still wouldn’t delete him even after I asked because they wanted their friends list to be as big as possible so they’d look more popular and relevant. Fuck that noise. Not worth the hassle. FB’s been deleted for years now.