I’ve been on the other side of this as well. I was 2nd female in a 4 mile road race, running with the lead woman. Some high school kids were on the course, we thought they were in the race, and followed them off course, adding about a half mile. The third woman ended up taking the win despite being pretty far back, and you know what? She earned it. Never crossed my mind that she was responsible for chasing me down and telling me I was off course. So she got a $300 cooler and I got lots of crap for being horrible at directions.
In this case, the blame is squarely on the lead cyclist and organizer, and they’ve done what they can to make it right. In no way are other runners responsible for ensuring their competition follows the course. It’s nice to do when feasible, and perhaps he could have shown more sympathy for his competitors’ situation, but it’s a stretch to criticize him for simply doing his job correctly.