We work with people in different countries. The "Out Of Office" calendar does not include public holidays, so it is not reliable, and it makes things very hard if we have to check various different countries - we currently cannot trust the appogeeHR calendar anymore.
A solution is that public holidays are recognized as out of office and people are automatically displayed as "on leave" on such holidays.
I opened a bug report on the same topic as it seems like a bug or a larger design issue that this is not the case. (Ticket 12834)