I don't mean to sound rude, and I am sincerely glad that you didn't run over anyone, but, honestly, this represents the bare minimum of driving competence. There's traffic on a road, and it's our responsibility not to hit that traffic. If there were a tree down over the road, or a large pothole, you'd be similarly responsible for not driving into it at full speed. If the lighting conditions make that task impossible at your current speed, the only responsible thing to do is drive slower. The Forest Service roads are full of such obstacles, as well as people driving cars, and log trucks, and OHV's, etc. That's the point of roads.
For some background on this kind of group ride (it's a social riding group, called Our Mother the Mountain, as paul2 pointed out), many cyclists started riding the gravel roads in our region in the last decade. In fact, this has become more popular all the world over.
The way you framed it ("Can't believe anyone would do such a crazy thing.. I'm still not hiking while wearing fur during hunting season.") makes it seem like the people doing it are irresponsibly glib about the safety of themselves and other road users, but the main reason people ride gravel these days is because riding on the paved roads around town feels unsafe.
Why are people seeking out gravel roads? Well, traffic in towns is worse, and gravel roads have slower speeds and less traffic. Gravel roads seem much safer to the people riding them.
- There's more traffic around town, for sure.
- Also, those big trucks that some people seem to love these days- the vehicles are wider, and they weigh more. Those massive front grills are actually far more dangerous, too, because they tend to hit at head height, and a human body can't roll up and over the hood ( getting knocked head on increases the impact force). This is part of the reason traffic fatalities are back up.
- There's also a lot of vehicular harassment (ask any rider), like "rolling coal," near misses, and of course shouting of all sorts, though I don't personally know if that's changed over time.
- As the quiet, paved farm roads around town turned into Google Maps cut-throughs tp reach subdivisions, and filled up with stressed, angry commuters, these paved roads became not fun for a bike ride, and feel very unsafe.
- Gravel roads, in contrast are slower (because gravel!), and usually have relatively less traffic (because fewer gravel roads go to neighborhoods).
- These rides are also beautiful- as the farms get eaten up by subdivisions, gravel roads are a remaining refuge of greenery and wildness.
For me, personally, I started seeking out gravel roads after I got hit by a pickup truck in my neighborhood. I was wearing a bright yellow rainjacket, in the middle of the day, lights flashing front and rear, and was following all the traffic laws. But, the driver didn't see me, and he drove through a stop sign as I pedaled through the intersection.
So if I sound like I've taken your posts personally, it's because I have!
It's like we can't ride anywhere without criticism and/or danger: classic rides around town (Skyline, Columbia River Historic Highway, Washington County) have noticeably more traffic, faster traffic, and bigger vehicles, and some people are now complaining that we riders should have the audacity to find quieter, less crowded routes!