The post mentions WHM/cpanel so it's entirely possible that it's ran by non-technical people who didn't have any backups of customer data because it didn't occur to them to take backups.
If you don't know WHM/cpanel is software for providing colocated hosting (pre-VPS days) in a turnkey manner. You could technically "own" a web hosting service and not really know what "Linux" is other than apparently something you're running on your servers.
But yeah you're right, under normal operations it really should be a matter of losing your most recent data or potentially customer data getting out. The bulk of your data should be intact somewhere if you're running the company properly. I'm guessing this company was not.