Why do some cultures or countries practice female genital mutilation?

The original idea behind it is to guarantee that the female does not want to have sex for the fun of it. in order to do this the removal of the labia and clitoris is a step in the right direction. if she is not a virgin she can not be married, so by removing the possibility of pleasure one is increasing the resistance unmarried sex. The next step in a society where respect for women is so low that rape would not be a big problem to many of it,s men is to sow the vaginal opening shut leaving just enough room for menstruation and urination now there is a situation where even the rapist is kept at bay. These traditions are so ingrained in some society's that mothers that have had this done to themselves will have the same done to their daughters in order to avoid them becoming outcasts in their cultures.