In general, superstitious behavior tends to win over non-superstitious behavior, even if it is a small minority.
For example, say there are two communities in a given town; one of the community has decided that black doors were evil, and won't go through them. The other community doesn't care.
Shops that have black doors lose the business of the superstitious community; even if that community is small, it simply makes no sense for a shop owner to keep a black door, whereas if the door is another color, it will cause no problem with anyone. And so, pretty soon there will be no black doors anywhere.
This may appear controversial, but the fact is you can't fight superstition with openness because openness accepts superstition and lets it grow and conquer everything. The only way to combat superstition is to actively fight it.
For example, say there are two communities in a given town; one of the community has decided that black doors were evil, and won't go through them. The other community doesn't care.
Shops that have black doors lose the business of the superstitious community; even if that community is small, it simply makes no sense for a shop owner to keep a black door, whereas if the door is another color, it will cause no problem with anyone. And so, pretty soon there will be no black doors anywhere.
This may appear controversial, but the fact is you can't fight superstition with openness because openness accepts superstition and lets it grow and conquer everything. The only way to combat superstition is to actively fight it.