The argument was for _how_ people react to Waymos. The OP said folks are more careful. The respondent said, no it's the opposite.
Neither argued that people do not adapt their behavior in the presence of Waymos?
Neither argued that people do not adapt their behavior in the presence of Waymos?
So the Waymo safety record is actually not their own achievement.
The fact that someone adapts their behaviour (regardless in what direction) still supports that claim.