@Red in STL - I'll respond to you here as well.
Its sad and not cool for those missing out but its not like there isn't precedent, stadiums have been closed before for racism (in Eastern Europe) but it has to be consistent and zero tolerence (which its not yet). I'm not talking about punishing 5 fans when the number is small they can be dealt with individually, I'm talking about when its in the hundreds or thousands. We can't just let it go on as is sadly.
Every time I see a fan of my club make an aeroplane gesture I'd be absolutely fine with targeting just them but when or if its numerous throughout the 90 minutes the FA saying "No fans for one game" and escalating from there would actually make me happy.
These morons who behave like this, have this weird thing where football is more important to them and its almost a parasocial relationship with their club. Their clubs are more important than families in some cases, we all know how for example domestic abuse spikes when teams lose etc... When they know what they are doing is affecting "their" club, they'll stop, their beliefs will not change but the behaviour will.
I imagine for the first while it'll be chaos but isn't short term pain worth it to allow 15% of the global community to attend a game without feeling like they don't belong or are 2nd class citizens or in the case of racism far greater than 15%.
You did make a great point about the regular people having to stop it McGrathsipan but whats gonna motivate those who normally sit by and do nothing through indifference to step up and tell these people to stop, its when the knock on effect hits them.
This problem seems to be much deeper in football than say rugby audiences or cricket audiences because its been allowed to fester sadly. You guys are well intentioned but an iron fist is what I believe is the only solution.