It is one of the many grotesque things we see humans engaged in. From wars to the slaughter of animals, there are many such things that are forms of blood sacrifice.
The thing of not is that event happens once a year in that village. Imagine the slaughter of animals for human consumption i thousands of "villages'; around the world. people will be outraged at the yearly dolphins slaughter but think nothing of the daily animal slaughter and even defend it.
To point it out earns people names like vegan nazi. Up is down and down is up.