As much as Team Evergreen preaches bike safety, its a pretty social group, and I can't help but wonder whether some of the riders were riding two or more abreast, which is not good and which can trigger drivers.
I'm hoping that I don't come across as uncaring, because I absolutely believe in the cyclists right to ride on the roads, and I'm not (in any way) condoning motorists hitting or even getting close to cyclists who are on the roadways.
That being said...
When I lived in Michigan, the excavation business I ran was on a country road (Old US 131/Mackinaw Trail) which was pretty hilly.
There wasn't really a good shoulder on the roadway for cyclists because it was an older hwy, but it was a main line between Grand Rapids and Cadillac for cyclists.
It was frustrating when our truck drivers would come upon cyclists riding three abreast on the roadway. Mind you, I (and our drivers) know that they had every right to ride three abreast, but that doesn't eliminate the frustration when a big truck, is trying to keep momentum while navigating the up-hill and down-hill traffic.
Imagine coming up over a hill with a tractor/trailer loaded with construction equipment, to find cyclists. Now you've lost your momentum and getting up the next hill is a little more challenging.
On the side of the cyclists - Its also not easy to get off on the gravel shoulder with a road bike without risk of getting a flat, so I absolutely understand why they don't get off on the gravel shoulder.