Races are usually run counterclockwise because it is believed to be easier for right handed people, who make up the majority of world population. Putting their right foot forward and leaning into a turn feels more comfortable and provides more power and balance than the reverse direction, say physicists.
Going counterclockwise also looks more natural, with runners passing
the observer in the way most people perceive, think, and read; that
is left-to-right. Easy to understand why counterclockwise was chosen
standardizing international competitions.