He's not done his robots.txt properly, he's commented out the bit that actually disallows it

  # silly bing
  #User-agent: Amazonbot          
  #Disallow: /

  # buzz off
  #User-agent: GPTBot
  #Disallow: /

  # Don't Allow everyone
  User-agent: *
  Disallow: /archive

  # slow down, dudes
  #Crawl-delay: 60