I think this is a bug, or at least, UI inconsistency.
My privacy mode is on, meaning that history is disabled. If so, why does "Recent" still showing on Files sidebar? There's no purpose for it any more.
This issue has been raised here: https://github.com/elementary/files/issues/1167. Pressing the Recent bookmark with history off displays an informative message with a link to the Privacy settings so it is not entirely useless.