The reason for this ban was that the presence of these new, noisy, and fast machines scared horses. At the time, horses were the primary mode of transportation, and the sudden appearance of automobiles caused them to spook and bolt, leading to accidents and chaos.
This ban was an attempt to preserve public safety and maintain order in the parks, which were popular destinations for horse-drawn carriages and riders. It wasn't until the early 1900s that automobiles became more commonplace and regulations around their use in parks began to change.