I still think it neither completely unpleasant nor entirely unexpected.
Big problem here might be finance for universities. Renting out the halls for conferences of any kind was, I think, what happened at Easter. And summer.
The current situation is as difficult and worrying for a lot of students and their families as it is for everyone else, especially the ones away from home for the first time, the ones who've got partners in their home towns, and so on. Being told they can't go home is going to be pretty devastating for some of them.
Conferences don't happen much over Christmas, but it would cost to provide cleaning, catering and so on, and a lot of institutions' finances are badly stretched as it is.
There might be good medical reasons to do this, but if it does happen it's not something to be taken lightly.