The seller has every right to sell to whomever he pleases. However, it's kind of a gentleman's agreement that when someone calls dibs, that they have first crack at it. The seller decided to sell to someone else. Was it someone that contacted him only via PM? A buyer locally? I don't know. To your point, I was very quick in responding, the ad was only up for four minutes when I called it.
You guys that bought these are getting great deals for sure. Enjoy and ride safe.