Tradition in most cases =/= common sense.

Bullfighting traces its roots to prehistoric bull worship and sacrifice. The killing of the sacred bull (tauroctony) is the essential central iconic act of Mithras, which was commemorated in the mithraeum wherever Roman soldiers were stationed. The oldest representation of what seems to be a man facing a bull is on the celtiberian tombstone from Clunia and the cave painting "El toro de hachos", both found in Spain.