It's not a team race, who cares if they train together.
They're job as professionals is to entertain the fans, it's what they get paid for. The fans didn't tune in to watch teamwork, but an individual competition. So they failed to do their jobs.
The fan has a right to jeer at a bad performance. It's the duty of a pro athlete to be jeered at when they do badly. If you liked that crap finish, go buy the advertiser's products and run in that marathon to support them. But don't interfere with the time-honored right of the dissatisfied fan to jeer.