He's saying that the problem is with "serverless architecture", because the problem could not possibly have happened without the use of a serverless architecture (e.g. provisioning a server). The problem is exclusive to serverless.
That's simply not true. You can accidentally run up huge bills with EC2 instances too. One typo in your CloudFormation templates could spin up a ton of reserved p2.16xlarge's.
Of course, if you consider EC2, and other AWS services, to be "serverless" too - you're not physically managing your own racks after all - then, yeah, fair enough, it is a problem exclusive to these "serverless" IaaS/PaaS providers.