HTTP is based on/using TCP, as many other protocols do, like FTP, SSH, SMTP, IMAP and so on. They are using features of TCP (like stateful connections, resend when a packet is lost etc), but how data is structured and transfered is up to the higher level protocols, like HTTP.
Actually, you can transfer data using only TCP, but this is more of "Possible but nobody does it" thing, as TCP itself has no comfort or features for doing so.
So - the article is correct. The video files are delivered via HTTP or Bittorrent Protocol, which are both using TCP for the transfer, but doing it "their own way".