FTA: “The black card being brandished will be the final part of a three-step process. In the first instance, the referee will temporarily suspend the match and ask coaches to speak directly to its team’s supporters and parents, while an announcement will also be communicated to supporters should a public address system be available.”

So, that’s exactly what step one of this is: a signal to the crowd “behave yourself/make the bad actors behave themselves”.

I’m sure the league has considered less drastic actions, and in reality a group of administrators dealing with an ongoing problem know way more about possible solutions that are available and can possibly work than random HN commenters.