The phrase in the title is a common trope that comes up when VPN services are discussed. While this statement is technically correct, it can be misleading, as it implies that all providers handle law enforcement requests and prepare for worst case scenarios similarly, so their conduct cannot be a differentiating factor when you evaluate them.
I worked directly for one of the two biggest log and search systems for big data for years and I can tell you that there is always a way to correlate data lol. And the data you don’t have you can always buy to help put the missing pieces together.