The statement "sports have losers" is true because Humans have a need to dominate and shame one another.  In addition, they have a need to watch this happen.  Sports are an organized human activity that place these desires in a context which allows humans to consider themselves civilized when they dominate and shame each other.  Those who dominate and shame are called the "winners" and those who are dominated and shamed are called the "losers."  Who is so designated is determined by the "score."  How the domination and shaming is accomplished is determined by the "rules."