For two reasons: the banking, which brings to mind an oval circuit, the bricks used under the layer of asphalt, such as the brickyard. Though the Indianapolis corner already existed at the first edition of the 24 Hours of Le Mans in 1923, the road was practically flat in that area, but as of 1928 the banking effect facilitated a noticeable trench with the continuous passing of competitors. It must be said that at that time only part of the route was paved, however not the case with the Indianapolis corner!
Photo (Copyright - Archives/ACO): The #11 Porsche 962 of Kremer Racing (fourth) in the Indianapolis corner at the 1987 24 Hours of Le Mans.