Obama no show at church

My priest once made a joke that there is a certain type of Catholic called C&E Catholic: Catholic and Easter Catholics. These are Catholics who simply do not attend Mass very often, but will still go on those two days.

However, Barack Obama didn't even go to a Christmas service. I understand he's busy, but missing the Christmas church service is going a bit far. I think he should be honest about his religion. He says he's Christian. It would seem Christians would have an obligation to attend churches services at least sometimes. Every President before him went at Christmas.

I'm not judging Obama's soul or saying he's a bad person. I'm just wondering what's going on here.