They're talking about breeding by humans over the last 5500 years, which is nothing on an evolutionary scale. The eohippus was a small dog-sized creature 55 million (note: not 55 hundred... that's four order of magnitude more) years ago... so much for your "never"...
However, the Equidae family tree does include the Equus, so you may rest assured that your ass is included in that evolutionary lineage.
None are so blind as those who refuse to see.