I gave that benefit of doubt to FB but still doesn't explain why random posts turn up at random intervals. Even it was to with CAP, I'm convinced that there's some amount of dark pattern involved just from the fact that 'user is not allowed to perform intended action'.

This is more likely the case then some conspiracy against users.

Software bugs in practice are rarely caused by fundamental problems. Sloppiness, incompetence and, in this case, different priorities are much more likely. Removing data is not a priority for Facebook.

People like to invoke all those theorems from computer science. That gives them an air of being knowledgeable. But at the end of the day, it's much more common that the program malfunctions not because of the halting problem, but because the language it was written in doesn't do bounds-checking on arrays, someone made an off-by-one error, or someone copy-pasted some code and the objective of the system was data collection, not data deletion, so the task of reviewing and testing the code was deprioritized in favour of something more profitable.

But talking about how you struggle daily with the fundamental problems of the universe sounds so much cooler.

Did you mean to reply to the parent comment?

But also, going by your logic, whatever is going on here is because something was depirioritized in favour of profit. The issue with that though, is that improper deletion would be detrimental to metrics in my opinion, not positive.