No, you needed to read the rest of the sentence:
Though Binney and a number of others left the NSA when it instituted the illegal wiretap program, Stellar Wind, Drake remained at his post — and tested ThinThread to “find out if there’s any information of the 9/11 attack that we should have known about but didn’t,” he explained.
Binney left, but Drake stayed. Drake tested the system that Binney had developed, and found that it did indeed identify information that would have warned of the 9/11 attacks. The system that replaced it (only a few weeks before 9/11) missed the info.
A number of people have posted that this is Monday-morning quarterbacking. But, in data analysis and data mining systems, "look-back" testing is essential to determine the effectiveness of algorithms and methodologies. It's typically called a "validation" exercise. If it doesn't identify known events, then it is likely to miss unknown events.
I doubt the original system that was cancelled has been updated since 9/11. So, it's very likely it would have identified the information warning of a terrorist attack. However, it's worth noting that doesn't mean the information would have been acted on.... we already know that one of the future hijackers had been detained by the FBI and despite an agent's best efforts, they didn't follow up on the possibility of a larger plot.
To act upon the information would have been deemed to be racist and profiling.
James Woods alerted the FBI to one of the dry run flights a month before the attack and there was no action. The FBI didn’t confirm they were among the terrorists but Woods has said that at least 2 of those on 9-11-2001 were also on his flight.