Why are Dates Editable in View-Only Data Forms?

I have a Data Form with parent-child relationships and a few children. The Page is in view mode. So all of the fields in the parent and children are readonly, EXCEPT for dates. Why would that be?

So when the user clicks into the field on a Data Entry form, a calendar appears, set to whatever date is contained in the field, or today’s date if the value is null. Of course, there is no way to save a new date to the database, but this behavior raises the expectation that dates can be changed.

And within fields with null date values, “yyyy-mm-dd” appears as the value of the field.

How can I make date fields readonly like everything else, and fields with null values be empty?