The reason why is because that specific AMD Processor is strictly a OEM/TRAY processor and not sold in Retail stores. This specific processor is sold in bulk to OEM manufacturers like Asus, HP, Acer, MSI, Gigabyte,etc.
You might be able to find one at Ebay or Ali-Baba or some other foreign Retailer but it won't have the 3 year AMD Warranty since OEM/TRAY processors are Warrantied by the Distributor or Vendor selling the processor and not by AMD.