The reason he hit the ramps fast was that he was trying to load the pickup without power, and apparently was too cheap to invest in a good winch.
The ramps were designed with a triangular corner to prevent sagging. When the tow vehicle rolled forward, it caught the front corner of the ramps and popped the ends up.
No idea why the emergency brake wasn't set, and perhaps also blocks under the tires, but hindsight plans are always better than foresight plans.