There is no clear beginning of this tradition, therefore the reasons remain unknown. In 1908 when the Wright bros performed the first flight nobody clapped.
It is a very divisive issue. Cabin crews find it offensive.
The female clothing trends are clearly going in a direction that shows more than covers. Shall we put lipsticks on the pussies? Why not? Revenues of cosmetics companies would double overnight.
GRATIS is a Turkish brand that offers items at doubled prices with the promise to let you have the second less expensive item for free. This weird business idea could work only in Turkiye.