For what it's worth it wasn't intended personally at the person who almost incurred the $72k bill, but more at the general concept of test/beta software gone rampant and out of control in an environment where billing has no limits. I think we've all tested some sort of software in development environments that caused havoc - but up until very recently it's been hard for that to immediately begin causing real world financial consequences...
IMHO the best argument for 'why not' would be that it's generally unethical to deploy software without first taking the time to read the manual and understand how your dependencies work. In this case the system wasn't live and the costs of this fuckup were solely externalized onto Google, which is fine because it was in large part their fault anyway. But when dealing with production deployments, this same behavior often results in users having all their private information leaked or deleted.
https://news.ycombinator.com/newsguidelines.html
p.s. I skimmed through your recent commenting history and it looks great—just the kind of thing we want here. Sharing some of what you know is exactly what we want users to do. But please don't be supercilious about it, as in this comment and https://news.ycombinator.com/item?id=25372847. Ignorance doesn't deserve humiliation, and that ingredient poisons the ecosystem (and eventually starts a degrading spiral, e.g. https://news.ycombinator.com/item?id=25373520). The rest is good.