It will forever be known as The Great Oops.
There are a few things that can cause tremendously widespread outages, essentially all of them network configuration changes. Actually deleting customer data is dramatically more difficult to the point of impossible - there are so many different services in so many different locations with so many layers of access control. There is no "one command" that can do such a thing - at the scale of a worldwide network of data centers there is no "rm -rf /".
The possibility Google will either manage to unleash a malicious AI on their infrastructure and/or develop a way to destroy a lot of data at scale quite efficiently or some combination of the two is far from zero.
Bear in mind, this "Little Oops" should also have been impossible: https://www.techspot.com/news/103207-google-reveals-how-blan...
Break your control plane, and you can't stop the propagation of poison.
Propagate the wrong trust bundle... everywhere.
Also, it's not about the delete command. It's about the automatic cleanup following behind it that shreds everything, or repurposes the storage.
If didn't back it up yourself, it is gone forever.
Though I'm sure the major players are all over this risk which is why it hasn't happened.