As an active cyclist, I will cheerfully agree some cyclists are ***holes.
But then so are some (many) motorists.
A lot of conflict could be avoided if both sides would obey the traffic laws and if these laws were actually enforced against cyclists, which they seldom are in most places.
My understanding is that the aggressive mass action bicycle fanatics are concentrated in just a few areas, all dark blue.
San Francisco especially. Strangely enough, I've rarely heard of these types of problems in Berkeley, near Stanford University, or even in Silicon Valley. (Probably because in these places, bicycle riders are more common but don't have the "holier than thou" attitude of the Critical Mass riders in San Francisco.)