Linked article conveniently forgot to mention the relevant footnote from original article:
> This may seem paradoxical, since atheists and agnostics have very low levels of religious commitment and yet score very well on the survey questions. However, atheists and agnostics account for a relatively small share of the total number of people with low levels of religious commitment; 4% of Americans describe themselves as atheists or agnostics, while fully 35% have low religious commitment. Atheists and agnostics answer an average of 20.9 questions correctly, compared with an average of 15.4 correct answers among people with low religious commitment who do not describe themselves as atheists or agnostics.
Btw survey questions them selfs are a bit nitpicky.. (who cares if jesus realy changed water into wine or if that was just symbolic)
Religious people seem to care quite a bit about whether the bible is literally true.
Further to that, some religions also heavily use traditions that don't appear in the bible at all. Catholics, for example, are meant to believe that the sacrament literally turns water and wine into the flesh of Christ. As in, it's actual flesh and blood (Transubstantiation).
So either Jesus was a walking breadstick or Catholicism as it is currently practised is obviously wrong.
There are so many varieties of Christianity based on "those other christians are definitely wrong" that I guarantee you somebody cares about those distinctions.