Normally I would say what the first family does or doesn't do on Christmas is nobody's business. But I think it IS relevant, because as a politician and now as POTUS, has made much of his religious faith, because he felt he had to in order to get elected. His liberal base tends not to be church-going, and normally has an adversial relationship with all things religious, but they're willing to look the other way because they know their guy "needs" religion to get elected. If you're going to criticize that as a cynical view I would ask you to consider this:

How many people who consider themselves persons of faith DON'T go to church all year and then go at Christmas and Easter (referred to by some as  CEOs (Christmas and Easter only). Barack Obama has made much of his religious faith as a candidate, and his family didn't make it to church on Christmas and hasn't found a church home in DC. Again, normally, I wouldn't care, but it's Obama who wore his religion on his sleeve...