It's not uncommon for humans to eat flesh. Since times immemorial, history has redeemed that in order to survive, homo sapiens have retorted to different means of dietary functions.
Some have restricted themselves to being vegetarians. Other non-vegetarians, as if to strike a balance between the two, believe in practicing a subtle form of cannibalism ― all in the name of inner peace and tranquility.
Despite improvements in the Hindu society's horrid caste system, that believed in racially dividing people based on their caste, there still exists sections of educated, or emancipated men and women who allow the Aghoris to practice the grotesque act of devouring a piece of dead rotten human flesh. Especially if the corpse has just been reduced to ashes.
The Aghori
The Aghori ascetic considers himself to be a symbol of the Lord Shiva (the last from the trinity of Brahma and Vishnu according to Hindu Mythology).
He goes naked or is dressed in the shroud of a corpse, covers himself in the ashes of the cremation ground, a polluting for an orthodox Brahmin, and his, and sometimes macabre, ritual actions are symbols of his non-dualistic beliefs.
The corpse upon which he meditates is a symbol of his own body and the corpse devouring ritual is a symbol of the transcendence of his lower self and a realization of the greater, all pervading self.
Their Doctrine
Because of this monistic doctrine, Aghoris strongly believe that there are no opposites in this world and that the conventional Hindu distinctions between purity and impurity are actually an illusion of some sort.
They live on cremation grounds, smearing themselves with the ashes of corpses and eating from a cranial begging bowl. They eat corpse flesh, which may be a once in a lifetime ritual act, and meditating seated upon a corpse and thereby gaining control over the corpse's spirit.
They have also been accused of practicing human sacrifice. The Aghoris claim to perform a secret Tantric ritual involving sex with a lower caste, menstruating woman during, which the Aghori becomes Shiva and his partner Shiva's female energy or "Shakti".
The purpose of embracing pollution in these practices is realization of non-duality through transcending social taboos and seeing the illusory nature of all conventional categories.
Most people who 'understand and accept' this religious act of subdued cannibalism believe that Aghoris can be accepted in society. As living in a democracy, it's not uncommon to observe such eerie acts of religion. Since practicing this needs loads of perseverance, Aghoris are very small in number.
These devout followers of Lord Shiva, are convinced that this is not a cannibalistic act. Since the dead and often rotten flesh is not eaten raw, rather thawed in liquor, untouched by the human hand, and consumed by a certain self professed 'chosen' number of people.
These people look for small pieces of flesh at the Hindu cremation grounds and are identified by their shiny attire. Since, of course, the idea of eating dead flesh is quite repulsive, this rite is not practiced often, only once or twice in a span of four to five years.
Moreover, they believe that this act gives one an absolute feeling of catharsis, destroying every shred of hatred and bringing with it immense divine foresight.