Actually, no the article does not say biometrics are "something you know" ie. a password. It spends its entire time pointing out that biometrics make very poor passwords.
Let me quote one sentence from the article for you:
"For them [Customs] your fingerprint is only really used to verify that you are you
That was in the context of biometric passports.
That is actually the correct use of biometrics
"Don’t use fingerprints as if they were passwords. Being permanent and relatively-easily verified and obtained makes them great for criminal investigations or for certifying that you are who you say you are. But they’re not passwords because they’re not secret, they’re not revocable, and they’re very difficult to store securely."
Let me state that again