That first horse was like "alright but just this one time" and ruined things for all the other horses

It is evolution through natural selection but it is still most definitely evolution. It's a net directional change in the population. There isn't an arbitrary point where it turns from natural selection to evolution as the two aren't so simply separated.

I'm going to try to avoid treating you like an idiot like most people here have and instead try to explain some things.

Evolution is based in reality and our long study and observation of the world.

We can start by saying that we do not have to rely solely on ancient fossils for determination.

There has been a long running study of evolution in bacteria that has run since 1988 and over 70 thousand generation where we have watched genetic adaptation in real time.

This has been replicated by other studies which have been running for shorter times.

We can stay modern and go outside of the lab environment though. Frog species around chernobyl have turned pitch black in an adaptation to protect from radiation evolving pigmentation and protection.

Then there is a classic of science that we can confirm things from seperate independant sources. We can roughly catagorize species based on similar traits and did so for a long time before being able to confirm these lineages through DNA and genetic evidence.

Then there is simply the fossil record. We can look back at fossils throughout history and see plain evidence of evolution and adaptation over time.

I encourage you to challenge your belief and look further into evolution and you will find that there is a vast amount of evidence for it.

In the fossil record? Yes we do. In DNA comparisons of related creatures? In a roundabout way also yes.