This was an incredibly insensitive anti-Catholic NBC program, and they wouldn't dare make such crude jokes about Judaism or Islam. They'd lose their jobs or receive death threats if they did.
At my Grandmother's funeral my half-brother who had never been in a Catholic Church in his life decided to go to communion. Why? Just because. His only "church" experience was to be baptized during vacation bible school in the 7th grade.
It happens more than you think. People don't want to look left out. Others don't think it's a big deal.