"They". Again, it was one guy, who didn't have the full backing of his employer much "the FIDO group". Who made a suggestion, though it was written as a threat because he was bad at communication.

Not to mention the only way to blacklist a specific app from Passkeys is to use the AAGUID from attestation which means it only applies to attestation. A few pieces of software were providing AAGUIDs by choice even when not attested and Apple helped remind them that the spec says non-attested Passkeys should always just return an Empty UUID (all zeroes) in AAGUID. The people that are going to block non-attested Passkeys might as well block all of them, including Apple consumer Passkeys.