Pius XII: Yad Vashem Admits It Was Wrong. In Instalments.
It is very embarrassing to say "we got it so wrong we should all resign and apply for a job at McDonald's". Particularly when the people in question lead the Yad Vashem, the Holocaust museum visited by people from all over the world.
Therefore - and in order to avoid having to resign - the responsible for the museum have decided to back pedal a bit at a time, in order to look less ideologised, blind and stupid when the time comes to say "erm, aah, well, actually....".