I'm not saying the bikers right by any means, but I don't think they were wrong, either. Because of their size, motorcycles can be hard to see, so by driving in packs they increase their visibility. To merge through the pack can cause a safety risk, so I can see why this would irritate the biker that yelled at the OP's DH.
It is not another driver's responsibility to make room for you between themselves and the vehicle in front of them. It is your responsibility to make sure you can fit in that gap safely; if you cannot, you don't put your car there. Can it be courteous to slow down to allow another driver over? Yes, but not doing so does not make anyone rude. How would it be any different if there were three or four semis in the right hand lane blocking the OP's DH from merging over? If the gap between them was not sizably safe for the OP's DH to merge, what would he have done? Merge through them or slow down to move in behind them? With motorcycles, that safety gap needs to be a bit larger (hence why the biker was probably angry). I just don't see how the bikers were SS; to me, it is no different than any other traffic.
Catching up on the thread (20 pages to go!), but this caught my eye because of what happened to me today. There are two lanes that turn left at a stoplight onto a bridge in my town. At the other end of the bridge, only the right lane exits to another island, the other lane continues to another city. However, most people using the bridge want to go to the island. Which leads to some interesting lane changes.
Today, I was the last in a line of cars going over the bridge in the right lane. Cue a late model expensive car running the
yellow light and then starting to change lanes -- into my car! She wasn't pulling into a space between cars, she was pulling into my drivers' side door! I honked. Then she turned on her turn signal and tried to pull over again - into the side of my car! She just couldn't understand why I wouldn't stand on my brakes to let her in -- when there was no one behind me and she had entered the bridge after me. She actually accelerated and cut off a car at the far end of the bridge to get off on the island. The kicker is she probably thinks I was rude because I did not literally stop dead to let her in.