Don't know the facts here - and not trying to blame the rider. But it is a good opportunity to talk about risk mitigation and anticipation. Some scenarios:
1). Rider never saw the truck, but DID have an opportunity to see the truck (straight, flat road).
2). Rider never saw the truck, but DID NOT have an opportunity to see the truck (hill, curve, obstruction, etc.).
3). Rider saw the truck, anticipated nothing, took no risk mitigation.
4). Rider saw the truck, anticipated truck pulling out, but took no risk mitigation.
5). Rider saw truck, anticipated truck pulling out, took risk mitigation, but failed to mitigate the risk.
Which is most likely? Here is the OP's description:
...at the middle of the curve is a side road, on the side road is a pickup truck with a dent in the passenger side...
Based on that description, it sure sounds like scenario #2. So how might rider have saved himself?
Seeing he was approaching a blind curve, he could have anticipated anything behind around the corner, especially on "nice curvy road through a cow pasture." Maybe a cow in the road, a tractor, who knows? Good move to take? Slow the **** down on blind curves. Maybe he did - and he still hit the truck. If so, he probably could have slowed down some more. Nevertheless - it is a good reminder that while it may be fun to fly through the curves - with respect to a blind curve, slowing down is never really a bad idea.
In fairness to the truck driver - on such a curve, it is entirely possible he never had an opportunity to see the biker either. Difference is, he can only sit there for so long before making his left turn or pulling out - and he is going to already be going slow when he does. In some situations, there isn't much he can do, especially compared to what someone coming up on a blind corner can do.