Is this actually private data, or is it public stuff that's become annoyingly hard to view anonymously because Meta chose to stick it behind a login box?
Depends if another user can also access it, or whether the original author/owner of the data in question intends for it to be public. In Facebook's case, there are permission levels you can set on posts, including a "public" option (which isn't actually public though and will require a login anyway, but it can be any login) which would settle that debate quickly - hell I wouldn't be surprised if that option were to be hidden as to not acknowledge that a particular bit of data was explicitly posted for everyone to see.
> In Facebook's case, there are permission levels you can set on posts, including a "public" option (which isn't actually public though and will require a login anyway, but it can be any login)
Q: Have you tried this?
In a private browser session I started at google.com, searched for "site:facebook.com nextgrid", picked some random post, click through, and was reading the post without anything other than seeing FB's cookie banner. No sign of any login (which is good 'cause I don't have one)
I suspect it depends on your region, page/post in question and browser fingerprint. A post marked as public isn't 100% guaranteed to be publicly viewable. Sometimes you can view it but merely scrolling down on the page would trigger a login form for example (I've had this happen for pages that are definitely meant to be public such as businesses who'd have an interest in getting as many eyeballs as possible on their content).
I might be wrong and maybe the behavior is actually fully deterministic and isn't nefarious, but knowing the company behind it I'll assume malice until proven otherwise.
but you make it public for everybody with the publicly accessible login so it wouldn't be considered private data for the same reason news outlets can use your instagram images and share it widely without your permission.
you can't throw up a login screen but then allow people to post themselves that ends up in public domain because the login does not distinguish from public or permissioned user authorized to view your selfie pics.