To be fair, it makes sense that the AOA indicator/disagree features were optional since airliners generally don't have AOI indicators in the cockpit and airline

To be fair, it makes sense that the AOA indicator/disagree features were optional since airliners generally don't have AOI indicators in the cockpit and airline pilots generally aren't trained to use AOA information. These features were targeted at airlines who have lots of ex-military pilots. Their potential safety significance is probably more obvious in retrospect.