Well, I grew up in an interesting religion, called Christianity. The first art I saw as a little child were the paintings of tortured saints in the church -- blood drenched, squirming people in colorful drapery, gazing towards heaven, grinning in ecstasy. The center of the worship was a man nailed onto a wooden cross, crowned with a crest of thorns piercing his head. And again, blood is dripping all over his skinny body. For 2000 years people in the western world grew up with iconography, songs and rites that glorify blood, pain and death, and God, the creator of the whole universe is allegorized as a bearded man dying in anguish. In this tradition, blood got a deeply symbolic and mystic significance and meaning.
The greatest artists of the Occident have depicted blood in so many aesthetic variations in the most beautiful paintings, so that these images are deeply imbedded in our collective subconscious memory.