Personally, I blame the parents.
People who can't handle loss need better parents. Stricter on videogame playing time. Clearly too many videogames are bad for teens and younger. They cannot be socially developed in other aspects in life. Too much value is put onto the game. People aren't secure with a loss because they aren't secure with themselves.
If you play as a hobby, and are good at something else. Videogames aren't your identity and self worth. Too bad parents are lax.
Grow up and deal with it. I lost my last 3 games and have been honored each time. What's your excuse?