Firstly, you have to be able to criticise respectfully, call out poor officiating, mistakes made, have robust, frank discussions, to stop that would be nonsensical, kill debate, we learn things from one another through such discussions, we are sometimes ignorant of the rules of the game ourselves, we see things differently from our viewing positions. The issue is how we go about doing it surely, language used is so important I guess.
I believe that the Professional game and grass roots need to be looked at independently and may require different interventions. You would need to identify what constitutes abuse, try to identify a reasonable line in the sand, particularly as we all have slightly different definitions of abuse as well as different tolerance levels. You can not sanitise the game to such an extent it detracts from the spectacle, the competition, the atmosphere etc.
The only way abuse in the professional game will eventually be vastly reduced (it can never be stopped when dealing with humans) is by changes within the laws of the game introduced by the regulatory bodies within the professional game and filtered down through the various leagues. The introduction of sin bins, Microphone recording referees, possibly bodycams, so that the perpetrators can be regularly named and shamed through evidence from these recordings. Hefty fines to player and club, plus appropriate bans would also be part of the interventions needed. That would eventually limit the abuse of officials from players on the pitch.
In the stands, well I’m not sure how this can be realistically achieved under the current law. You can have robust stewarding, warnings to fans, temporary bans, permanent bans, fines. Each club would need to agree a set of guidelines, be seen to administer them reasonably equally and fairly with some sort of appeals system. The sheer cost involved would likely be prohibitive the lower down the pyramid you went, ironically abusers would probably be more easily identified, would stand out more though, but in turn that could also mean improved self policing as a result.
The grass roots is where UK law has a more interventionist role and where we need better examples set by parents and well any spectators really, club coaches too etc. The professional game also has a duty to help get the message across that abuse is never an appropriate reaction, whether to a ref, player or anyone else for that matter. I would like to see better funding to grass roots from the professional bodies to enable refs to be miked/ bodycammed etc at that level, abusive attendees be filmed by respectful attendees and have some sort of temporary banning orders for serial abusers leading to permanent ones, even criminal prosecutions where deemed appropriate by the police.
It is such a complex area, but the best place to start is with yourself as an individual. We choose how we react, increased self awareness, robust reporting systems, most people have the ability to record anything on our phones. The game needs a thorough and serious review from top to bottom with appropriate, realistic and affordable interventions that don’t detract from the sporting and atmospherical elements of the game.
Having said all that, I don’t think the will is yet there to tackle it properly.