Biking on the left, the right and the middle

Marc and I are bikers so to anyone who reads this and starts to take offense, don't think we don't know how it feels to be run into the gravel, over the side or pushed by a mouth-breathing car inches behind your bike.
But Saturday as we drove over the Alpine Loop to see the changing leaves, we met some guys who give us all a bad rap.
We were coming from the Sundance side early in the day so as to avoid the heavy traffic and we weren't in any particular hurry.
We were just cruising along enjoying the spectacular sights and trying to avoid collision with the cars, trucks and RVs coming around the numerous blind curves.
Basically, with the windows open and the radio playing, we were averaging about 25 miles an hour when we came up a pair of guys biking in front of us.
They were sort of on the side and sort of three feet in the middle so Marc didn't dare pass them until he could get a clear shot.
He slowed to about 10 miles an hour (It's obvious that it's not an easy climb for bikers and the road is not very wide at all with no usable shoulders for the most part).
We plugged along for a while when we saw a curve coming up that had a partial turnout on the right.
Marc thought the bikers were pulling over to let us past so he accelerated just as a big car came around on the left with a biker person in the middle.
The two bikers ahead of us did NOT pull over but instead burst out in front of us, causing us to have to brake hard and veer to the right toward the drop-off.
It was scary there for several minutes.
We were happy to avoid disaster but apparently somehow through it all we offended the bikers because now there were not only ahead of us but WAY out in the road.
The one guy was on the side but the other was about six feet out, making it impossible to pass him even without oncoming traffic.
He stubbornly held his position for several more miles until we came to the Cascade Springs turn-off at which point he stopped and hollered something rude at us as we went by.
I'm still trying to identify our sin, our mistake.
Were we not entitled to some of the road?
Was there somewhere else we were supposed to go?
If we hadn't been careful, we could've killed everybody.. and eventually the traffic backing up behind us might have run out of patience, don't you think?
I realize that these guys need to be cut a little slack and when we saw a lone biker holding up miles of traffic coming up from the other side, we sympathized both with him and with the cars behind him.
But seriously, hogging the middle of the road on purpose?
What does that accomplish?