>Dealing with mentally ill people is anxiety-inducing because they act unexpectedly... so what? Lots of things are unexpected.
I think you're understating it.
Mentally ill people act far off the cuff. If I'm walking outside, people can behave unexpectedly (but within the parameters of behavior that doesn't make me anxious).
Imagine: stopping instantly to bend over and tie one's shoes or to look at a storefront. Taking up multiple spaces on the sidewalk. Dropping an item that causes a loud noise. All of these are unexpected movements that require a reaction.
However, if somebody screams about CIA conspiracies or has very erratic mannerisms, that would create more anxiety.
So, apparently their point is that AI behavior on the roads might be more jarring than normal jackass human behavior on the roads.