Looking online briefly for definitions of "delete":

"remove or obliterate (written or printed matter), especially by drawing a line through it or marking it with a delete sign."

"synonyms: remove, cut out, take out, edit out, expunge, excise, eradicate, cancel"

All of these seem clearly "absolute" to me. "Delete" means it's gone.

I think Facebook has its own special linguistic distortion field. It requires no "dumb conspiracy theory" to realize that Facebook cannot be trusted.