Earlier quoted context omitted.
How did markets function prior to HFT? You had 10 very tall loud guys in brightly colored jackets yelling at each other in a pit. Mentally they were running the same algorithms as HFTs, just slower. Later on you had some fast fingered guys watching charts and mentally running the same algorithms as guys in the pit, just a bit faster.
Except the people were exploiting inefficiencies in markets ( and still do today ). HFT algorithms exploit inefficiencies in servers, ISPs, fiber optic cable, a competing algorithm's implementation, etc.
Exploiting inefficiencies in a competing algorithm is the same type of thing as exploiting inefficiencies in the mental model of the guy standing next to you. Taking advantage of better market proximity is the same type of thing as drinking less than the other guys in the pit.