I would agree that it doesn't seem like much. But the article says that the director of the wuhan institute's BSL-4 laboratory wrote in 2019 that “Maintenance cost is generally neglected ... Some BSL-3 laboratories run on extremely minimal operational costs or in some cases none at all.”

Most importantly, "the WIV housed numerous laboratories that worked on coronaviruses. Only one of them has the highest biosafety protocol: BSL-4, in which researchers must wear full-body pressurized suits with independent oxygen. Others are designated BSL-3 and even BSL-2, roughly as secure as an American dentist’s office."

"Shi Zhengli herself had publicly acknowledged that, until the pandemic, all of her team’s coronavirus research—some involving live SARS-like viruses—had been conducted in less secure BSL-3 and even BSL-2 laboratories."

There is apparently a history of SARS escaping from Chinese labs on multiple occasions, and the bat coronavirus from the mine that was human transmissible was the "only one whose genome closely resembled SARS". And according to the Wuhan lab itself, the coronavirus is "96.2%" similar to this sample, though they tried to hide this.