Why is "believing in God" a component of "going to youth group"?

It is not always the case, but it most definitely is the case in this specific situation. She is noticeably converting to belief in Christianity (and not belief in belief or belief in sports teams, as far as I can test).

Then, I was arguing it's worth converting to Christianity in order to get friends. Which I do believe is the case for this particular young girl; I just ran into my deontological rule "don't convert to Christianity" while discussing it.