In this context the entirety of IBM cloud is basically a single storage point.
(If IBM was also running the local storage then we're talking about a very different risk profile from "run your own storage, back up to a cloud" and the anecdote is worth noting but not directly relevant.)
If that’s the case, then they should make it clear they don’t provide data backup.
A quick search reveals IBM does still sell backup solutions, including ones that backup from multiple cloud locations and can restore to multiple distinct cloud locations while maintaining high availability.
So, if the claims are true, then IBM screwed up badly.
(If IBM was also running the local storage then we're talking about a very different risk profile from "run your own storage, back up to a cloud" and the anecdote is worth noting but not directly relevant.)