Edit: The question and its tone has changed since I answered it. The original question was, "I have heard that Muslims in India don't use toilet paper after they poop, they just wash it directly with their hands. Why do they do that? Isn't that disgusting?". The OP came across as a troll which is why I had adopted a somewhat confrontational tone in my answer. Generally speaking, I don't give a shit (pun intended) about people's toilet habits :)

If you had shit on any other part of your body, would you be content wiping it with just a piece of paper? Because that would be disgusting.