Imagine if the SEC refs took themselves this seriously

Am I supposed to watch a 10 minute video?

It's about flow of the game, first and foremost. American football inherently has stoppages, so a ref pausing to deal with a coach going ballistic is very different. Rugby is supposed to keep moving without the stoppages, so a player or coach interrupting to argue has to be addressed more harshly to prevent it from being used tactically. There are also 8 (?) refs on the field for American football whereas rugby only has 3. They don't have as many eyes on the situation, so arguing serves less of a purpose because the odds are that no other official saw something to help. In American football, a coach or player yelling at the umpire may get the back judges attention who saw something that could alter the way the play was originally called (not that it happens often but does happen).

Soccer refs suck donkey dicks and take themselves way too seriously too.