The following link, published by the administrative team at the USA basketball program (sponsors of the US men's and women's national teams) , offers great suggestions on how parents can frame post game conversations with their children aimed at promoting healthy dialogue and encouragement.
https://www.usab.com/youth/news/2012/05/parents-guide-section-4-parental-dos-and-donts.aspx
The following link contains a link to a recent Washington Post article that discusses methods that spectators of youth sports contests can employ to promote a positive culture in the stands-with a particular focus on best practices to ensure that game officials are treated with the dignity and respect that they deserve!
https://truesport.org/a-good-sport/parents-support-referees/