That is a good point and obviously not something they can control much. I think more or less the goal is to help CMs put in these situations and remove or de-escalate any situations that may occur.Which is fantastic yet surprising tbh that it took so long for Disney to address abhorrent guest behavior.
But how does one prevent those interactions from occurring? Disney can't prescreen guests.
They also can't prescreen CM who would potentially engage in exclusionary behavior. The fact that it does happen is surprising but not unexpected in an organization that employs tens of thousands of people at a single location.