From Cynthia Freeland's But Is It Art?:

“…But audiences who see and react to a modern artist do not enter in with shared beliefs and values, or with prior knowledge of what will transpire. Most modern art, in the context of theatre, gallery, or concert hall, lacks the background reinforcement of pervasive community belief that provides meaning in terms of catharsis, sacrifice, or initiation. Far from audiences coming to feel part of a group, sometimes they get shocked and abandon the community. This happened in Minneapolis when performance artist Ron Athey, who is HIV-positive, cut the flesh of a fellow performer on stage and then hung blood-soaked paper towels over the audience, creating a panic. If artists just want to shock the bourgeoisie, it becomes pretty hard to distinguish the latest kind of art that gets written up in Artforum from a Marilyn Manson performance that includes Satanic rituals of animal sacrifice on stage.

The cynical assessment is that blood in contemporary art does not forge meaningful associations, but promotes entertainment and profit. The art world is a competitive place, and artists need any edge thy can get, including shock value. John Dewey pointed out in Art as Experience, in 1934, that artists must strive for novelty in response to the market:

Industry has been mechanized and an artist cannot work mechanically for mass production....Artists find it incumbent….to betake themselves to their work as an isolated means of ‘self-expression.’ In order not to cater to the trend of economic forces, they often feel obliged to exaggerate their separateness to the point of eccentricity.

Damien Hirst, the ‘Britpack’ artist who sparked controversy in the 1990s by displaying macabre high-tech exhibits of dead sharks, sliced cows, or lambs in vitrines of formaldehyde, has parlayed his notoriety into success with his popular Pharmacy restaurant in London. It is hard to imagine how Hirst’s tableaux of rotting meat (complete with maggots) helped his image in the food business – but fame works in mysterious ways. (4-6)