If he was not a dr. What was he supposed to do. Sit there and be a looky loo and clog the trail like the interstate when there is a crash on the other side. Maybe the sight of blood would have made him pass out and you would be tending to two riders. Maybe his wife went into labor and he was rushing home or just had to poop. There could be many reasons he didn't stop or just want to get by. If you didn't call him out on the spot and tell him what he was doing wrong right then. No need to do it here.
He's entitled to his KOM crap, but he just about caused another wreck with the other bystanders. Hopefully he might read this and be a little more courteous next time he charges up another trail en route to his glory. I'll be quiet now.