Well,
I am one of those that has been on all the sides of this.
First, a speed limit is a LIMIT.
Second, courtesy is a good thing.
What we don't know here is what was the capability and experience of the Class C driver. He may be new at this and think he picked a country road so as to not hold others up any more than he had to.
The only state I know has a "Tail Back" law is Alaska. They do their best to enforce it.
It all comes down to the fact that the lead driver may not have be happy with the turn-outs he saw or he may have had an issue that distracted him from taking advantage of them. It is, after all, the drivers responsibility to stay safe.
We don't really know the whole case here, do we??
Matt