Professional sports both man and woman should combined both good behaves and attitude with play will.
According to my prospective, i think playes have so many fans which are coping their behavior and attitude further more they take them as their role models especially those younger kids and teenagers.
Players are representing thier institutions and clubes, so if some player misbehaves in the field i thinks its reflect their club vision and values, a survey and study made in United States in 2015 about what's attracting team supporters in any club or sports, and the results came that 60% of people starts to like and support the club from one famous player which acts and play in a certain way.
Finally, attitude and behavior matters in any feild and area, specially in formal and worldwide institutions and industries and the most important in my opinion for sports because it's represent and connected to the player community, country and environment.