It all goes back to competence of referees and their ability to understand the game and the context of the game.
IFAB have tried remove the need for referees to figure out intent, which is why we ended up with the ridiculous handball rules. The same goes for the situation for Priestman where the rules have tried to create absolutes rather than taking context into account.
If the refs could be trusted to understand and appreciate footballing situations, we could let them apply common sense. Sadly, I don't see that changing any time soon.
On a slightly different note, regarding "ruining games for the paying public", I completely agree with that. I've often wondered if it wouldn't be better to allow a red-carded player to be replaced with, perhaps, harsher punishments for those that are red carded. In a sport that has tried many things to be more entertaining, a team going down to 10 men early in a game can spoil the spectacle for both sets of fans.
I know things like sin-bins have been trialled, but maybe that would another option for the Priestman situation. 15 minutes off the pitch. Or instead of a red card, always book the player and award a penalty even if it wasn't inside the box.
There must be a better option, even if it's not perfect.