Today, the only way to get permission-sensitive column-sums in categorized views is private on first use, which leads to hundreds of personal views in our databases that all want to be maintained. Once they get too many they can even cause stability problems of that application.
What we really would like to see is to turn things aroud: first build the user specific document collection of the view, then build the sums of the categories. Everything else makes no sense.
I assume this was done for performance reasons many years ago, but to have someone look at it now could lead to a different result.