In this case, it was not losing data, but losing access to data. The data was eventually restored. Lose customers' data could also mean losing the backup:

"We're sorry, the tape that we didn't needed to keep has been lost/zero-dayed/secondary service provider has gone bankrupt/Billy's house that we left it at got robbed." These must be disclosed to a customer immediately.

Minimising attack/liability surface is not only a technical problem, but a business one too.