If we take things too literally, the creation stories, world-views, miracles, re-incarnations, karma, heaven and hell, angels and demons assertions of different religions or spirituality must either be all wrong or only one being "right". They are most often mutually exclusive as statement of facts. Are these people superstitious?
The faithfuls believe in Moses separated the Red Sea. They are not superstitious. This can be interpreted as a metaphor of the power of God which exercised HIS power then, but refuses to exercise HIS power now! And based on this belief, the faithfuls will act morally and lead a happy life. And that is the power of a belief system. Unfortunately, with our modern scientific outlook, less and less people will be "motivated" to be a better person through this miracle of Moses (or as a matter of fact, other miracles!)
According to Jung and others, this is the problem of the modern man: An inner urge of a myth to believe in, but the lacking in such "believable" myths in modern times.
How about science? Scientific statements are tentative statements, they can never be turned into a belief system. Yet, some new-age spiritualists are fond of associating science or try to equate science with spirituality, or beg for scientific support for (their) myths. One direction is the so-called "evidence-based" spirituality, a comforting name but lacking in substance upon closer analysis. (you can check my view towards this approach HERE).
Science is simple. It only concerns statement that can be falsifiable (as defined by Sir Karl Popper), and statements of spirituality are unfalsifiable. These statement of spirituality have rich and useful meanings highly relevant to man, other than scientific meaning as defined above.
It leads us to our original question. Are religious or spiritual people superstitious?
If a statement cannot be falsified, it simply can't be proved wrong! The question is: Do we have a scientific statement (which is inherently tentatively and shall be superseded by a better scientific statement someday) that state a different path or scenario on a concrete situation of decision making?
A simple example, for a lady with stage one breast cancer, which path she should choose?
Scientific statement: a partial mastectomy will have, say, 90+ percent 20 years survival rate.
Superstition 1: Any surgical operation will result in a huge loss of my life chi, and therefore it will cause more damage than benefit.
Superstition 2: My God (or deity) will protect me, so I only need to pray more, and I will be cured.
Superstition 3: My friend told me that his uncle was cured by this exotic herbal medicine of this old "Taoist", and I shall do the same.
I guess, superstition oftentimes goes with ignorance....