Yeah, you're right. It's really useless to see art through the specs of reality.

In humans the left-brain is responsible for reasoning, arithmetic, speech etc., while the right-brain is responsible for creative and artistic skills. So mad people can definitely be more creative and artistic, even if they are weak in reasoning and understanding.

And even in some cases, a great artist eventually becomes mad, as to what happened in the Maugham's novel The Moon and Sixpence based on the life of the great artist Paul Gauguin.

There is no place for reasoning in art, it should be felt through heart and of course our right-brain.

An aesthete will see only the beauty of a portrait of Napoleon and won't care about who he was and what did he do.

Great thoughtful article. Thanks @geekgirl.