Good points discussed.
I'll admit to being one of those who might pass other riders closer than folks are comfortable with from time to time. However I'm not one of those who might shout "move over". I try and use good judgement when passing. If there is room to safely move over several bike widths and even into an oncoming lane I try to do so. Oncoming traffic, road conditions or sight lines might dictate how far over I can move. I've also startled some riders announcing when coming upon them to the point they instinctly jerk their bikes to one side or the other so I try and judge if that's going to be a problem. I'd hate to cause an issue with them unnecessarily. I'm comfortable with other riders passing me, even very closely but then again I'm comfortable riding in larger groups-rubbing shoulders, elbows, etc. I intentionally avoid cutting back in very quickly after passing as well. The main thing I try to do is pass safely-both for the other rider and myself.
We had a really bad situation similar to what the OP described a couple weekends ago on a large organized ride. There were 800 riders total and I was in the lead group of about 30. We missed a turn at about 20 miles into the ride, and went 12 miles off the route before coming back to the turn and getting back on the route. By that time there were hundreds of riders on the route in front of us. To make it worse we were on 2 lane rural roads that were pretty rough and narrow but fortunately not heavily traveled-but there was still traffic to contend with. Our group was riding significantly faster than the other riders (23-25mph vs 17-19 mph). Our group went from riding in a "bunch" to pretty much riding single file. We wound up eventually passing all the other riders and I'm sure some might not have been happy when we rode by. I think we did the best we could but at times there was oncoming traffic or other issues where passes might have been tighter than folks would have preferred. I avoided being out front and was riding in the middle of the group so I don't know what kind of communications was going on to alert other riders. I certainly hope the folks out front were pleasant as they came upon other riders-but am willing to guess that our more aggressive riding style probably didn't please everyone.
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Ride your Ride!!