Also why is there a generic Christian but then also Protestant, Catholic, and Orthodox? But then they just Muslim and not it’s different denominations? Why even have different denominations when you have the generic catch all and the Other category?

There are kinds of Christian that don’t fall under Protestant, Catholic, and Orthodox by their own measure (which doesn’t care how the Big Three want to categorize them). Perhaps this was why? (Probably not.) Graph should have just lumped them all together as “Christian”.