I can see an argument for the default behavior (though I would want the combined info too). But in case you or any other reader doesn’t know, hold option when choosing from the right click (or press cmd-opt-i) to get the “inspector” instead which will give you information about the whole group of files.

And related if you do open a mess of individual info windows, holding option while closing a window will close all windows in an application (note that since the info windows are in the finder, this will close your finder window too)