a few years after Pony made contact with humanity... yet racism still happens from time to time.
This unnamed human nation is in the early stages of automobile adoption. They have cars, but still sometimes prefer horses as a mode of transportation.
There are efforts from progressives to help stop racism between humans and ponies. Somehow, someone came to the conclusion that horse riders are more likely be be racist than people who use another means of transportation. They worked with animals that closely resembled ponies and unconsciously treated ponies as low intelligent animals too.
"End the horse-riding! Stop the Racism!"
ponies though the idea of a human riding on a horse is demeaning and it must be stopped. A great protest was ensured(help funded by car manufacturers to quicken automobile adoption).
But of course, things won't go as planned. The Equestrian government cared for its citizen on foreign lands and threatened to be less lenient at the next summit if their solution was to increase little ponies' chances of getting lung cancer from diesel engine exhaust.
To keep the political pressure down. The government came up with a bright idea and made it legal for people to use apes, monkeys, and gorillas as a stead.
But joke on them, riding monkeys becomes popular with the little ponies. The poor hanging traffic lights and telephone posts got abused by grabby monkey hands as the new stead animal swung across the city, taking its quadruple master with it.
Turn out Pony hated waiting in traffic as much as humans and swinging around like a spidermare was cool to them.
Soon, swinging around lamp poles would be accessible to humans as someone with a bright idea started developing a machine that could achieve the same thing while capable of supporting much heavier weights.
The 3d maneuver gears!