Well, is that an unreasonable assumption? With passwords knowing what one person's password used to be or even knowing one hash of their current password tells you nothing about a different hash of their current password. With biometric data points presumably if they get accurate and detailed enough (which you already admit they would have to do to be a valid authentication mechanism) you can extrapolate. Faces are known quantities. Knowing how 999 points of your face are arranged does give you data about how other points on your face are likely to be arranged. We already have modelling software capable of this, so it doesn't seem unreasonable that such methods may be improved if facial recognition gains traction. At the very least it brings down the solution space to a much smaller size the more data points are used, which is the opposite of what happens when more data points (characters) are used in alpha-numeric passwords.

>It's often frustrating to discuss things with those who clearly know little about the topic and yet declare their opinion as fact.

I would agree. Especially opinions like how others "clearly know little about the topic".

But is it as frustrating as someone explaining their reasoning for their statement and then you ignoring that reasoning to discuss their closing statement as the entire argument?