Belief in the supernatural realm is dangerous, because it denies the real world and tries to blame "the devil" or accepts passivly such things as tyranny, abuse, and evil. Such thinking does not lead one to learn, grow or expand, becuase "God will take care of you". Whenever suffering or injustice happens, it is chalked up to "God's training ground, because God doesn't allow anything to happen unless it is in his Divine Purpose, Plan and Will. Tyranny, abuse and evil in the world is not challenged, it is accepted as "God's rule on earth", whereas, each person deserves the right to exist, be respected and given opportunity.
Today, science frames our reality and understanding differently than in the past. Science is showing us more and more how the world works and what probably happened from the beginning. Humans may not be the only life in the universe. We just don't know for sure...
Where the Church used to teach man as the center of the universe, science undermined that understanding where it became known that the Sun was the center of our solar system and we are only one solar system in the universe. This fact alone is humbling to man, as he is not the ultimate focus of all things.
Man becomes responsible in this "universe" because he no longer depends upon a God out there, but takes on responsibility for himself. People do disagree as to what is the responsibility of man toward himself, the environment and others will be. And these differences are not easy black and white solutions in a world that is filled with diverse ways of understanding and thinking.
So, believeing is dangerous because it limits, defines and dismisses the greater questions about life, and the world we live.