Notice that Jews don't wear the red string. It is gentiles who follow Kabbalah who do. The reason is because they have unknowingly become a scapegoat and have the sins of the Jews foisted upon them. In the Torah there is a ritual sacrifice in which two goats would have red string tied around them. One was led into the wilderness and thrown off of a cliff. When the goat died the red string on the other goat turned white and at that moment the goat was sacrificed upon the alter of the Temple of Solomon. When a famous person wears the red string all of their Fans (as in Fanatics or worshipers) will bear the sins of the Jews. It is interesting to note that around the time of Christ it is said that the ritual failed and the string would no longer turn white.