There is a history going back to their college days. Clark is not above talking a bit of smack, after she makes a play. This is SO common with basketball at every level, wherever it is played. Within the contest between the teams, every player is also locked into an individual contest. You are literally bumping up against one another. Trading words is ubiquitous.
Clark is a transcendent talent. Reese is not. Reese is a tall strong woman whose coordination is pretty poor. Some of her misses are hard to watch. At a much lower level, I was a Reese type of player. I was a good rebounder and mediocre shooter. But, I never threw up bricks like that.
Last year, the WNBA players delivered many hard, at times, dirty fouls on Clark. The Chicago Sky were about the worst about that. The foul this past weekend was not a dirty play. It was a hard foul, to force a player to score from the line. It did not deserve to be a flagrant foul.