That's what the article implies, but I think it's overblown. They provide enough information (unfortunately) to identify the employee whose credentials were stolen, and she's a Sales Engineer. The data seems to have come from her own Snowflake account, which was used to build demos for customers or prospective customers. It's quite possible that those customers granted her access to some of their actual data, which was used in those demos, but it's a far cry from unfettered access to the customer's Snowflake database itself. It's also quite possible that the hacker exfiltrated fake-but-realistic data used for demo purposes and doesn't know the difference.