You have to use a separate method includingDefaultValueFields() to print the default value fields. Example can be found here.
Seems like you would want to see all your values for an enum type, including the default ones, as otherwise in your print results, you would see fields completely omitted for some cases. In my case, this led me to believe that certain fields were not set (which was wrong, they were just omitted visually). I'm struggling to understand why Google made this design choice.
Anyone have a clue?