In Paul Turner's Blog by Paul Turner

Q: I was surprised to see that the memorial of John XXIII is only designated as an optional memorial. Based on how significant VC2 was/is you would think that his memorial would be designated as mandatory. How do they decide who is optional and who is mandatory? Could it be based on the fact that John Paul II was canonized on the same day and his feast is also optional?

A: As far as I can discern, it’s a judgment call. The dicastery exercises restraint over which saints go on the general calendar and even over which ones go into the calendars of the conferences. Mother Teresa is another example of this. She’s popular right now, so many in the US would like her on the national calendar, but will her popularity remain in the decades to come? Will the witness of other saints better serve the future church? 

It could also be argued that Pope St. Paul VI was more influential than John XXIII in implementing the Council. It’s probably easier just to list John as an optional. I mean, even St. Patrick is an optional memorial.