Description
User, who does not have a value in a specific (People in this case) column, can not be found in a Filter.
Shouldn’t all users ALWAYS be discoverable in a Filter, so that the Filter can be made, also for future usage when user will have a corresponding Column value?
What are you trying to achieve
Creating a Filter, in a Dashboard view (using a People Column) but where user X does not have been set (yet) as a value for this Column.