I, of course, did not say that people of the medieval era were stupid. Probably their brains were as good as ours. The problem is that much of the 'knowledge' of that time was based on false information. For example, that the sun revolved around the earth.
Any scholar of the medieval age is well aware that there were many superstitions that have since been dismissed because we know better. It was easy to believe before we knew that germs caused disease that it was punishment from God or the result of demons or the work of Satan or whatever. Certainly we would view most of such ideas as superstitions today.
I have read the Church Fathers - many of them, even heretics like Origen (a favorite of mine) - and while they were brilliant for their time, when most people could neither read or write, their works contain many superstitions based mainly on ignorance of science. With limited telescopes and no microscopes they believed all manner of things about our 'three-tiered universe' and much else that modern discoveries have led us to dismiss as simply false.
There needs to be a certain respect for the wisdom of ancient times, but some good Christians, Catholics and Orthodox in particular, admire the past too much. We should borrow from it in many respects, but be ready to toss aside what is no longer found to be true or relevant to our current world. Otherwise the Church drives away more and more people who find it impossible to believe the unbelievable.
God bless his children of every (and no) creed, every color, and every country. May religion become a bridge and not a barrier.