There's a role for referees, too. The U.S. Soccer Referee Education Resource Center has published guidance on what constitutes insulting, abusive or offensive language and/or gestures. "The main principle in recognizing offensive insulting, or abusive language is that the referee must protect the safety and enjoyment of the participants as well as the fairness of the play."
The LOTG permit sanctioning coaches using insulting, abusive or offensive language during games with a red card and dismissal. This kind of behavior impugns the dignity of the game. Emotional abuse of players should not be tolerated.
We referees need to step up and do our part. A few years ago I spoke to a high school girls junior varsity coach during a game about how he was speaking towards his players. It probably didn't cross the line into the type of language the U.S. Soccer guidelines describe but I considered it demeaning and inappropriate for a leader of an interscholastic activity. Later, other referees confirmed similar behavior during their games. Thankfully, he was not the JV girls coach the next season. In retrospect, I regret not having written to his principal after my experience.