If the user has protected the content in the privacy settings, then it will not be possible to download it. Unfortunately, in this case, only the user`s followers have access to the video, and no web service will be able to open it. Since the downloader is anonymous, it cannot scan your following. So even if you are subscribed to a user but his account is hidden, then the scraper will not have access – you do not enter your login data.
But this principle of operation guarantees complete security and anonymity when downloading videos from IG.