Facebook is NOT a backup. If you only keep stuff in your Facebook account, then it is as 'at risk' as if you only kept on the hard-drive of your ageing laptop that you bought on discount in Walmart/ASDA ten years ago.
This oft quoted adage also applies: 'If you are not paying for the product, then you are the product'. The author seemed to think that Facebook owe him for some reason, and that he is fully justified/entitled in begging for his account back. Facebook is a private company who most of the time let the general public mingle in the lobby of its HQ[1]. As their lobby is still their property, they can refuse entry whenever they like.
Something needs to be done about Facebook's near dominance of the Social Media space. If we let this run unchecked for much longer, there won't be an 'internet' - just millions of stale, abandoned websites all simply redirecting you to their respective Facebook Pages instead. It also wouldn't surprise me if at some point, new phones will be released where the browser app is no longer installed by default, but the Facebook app is. Even if this happened today, most non-technical users wouldn't even notice.
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[1] Because the lobby is full of adverts from Facebook's business partners and Facebook gets a nice cut if you buy something being advertised.