I don't think anyone is questioning the coach issue at Luton. If the final would have been between two none UK teams then plans would be in place for this already. As it is just one now then it is a smaller logistics plan.
It is just the fact that it has been reported that you must use Stansted only is the talking point. It has capacity so is the logical choice.
Those football supporters who have a choice in their entry point will want to use an airport nearer to Wembley with 24 x 7.