Having ridden 100,000 miles plus in my youth, and bicycle commuted as an adult, I feel the need to enter the fray here.
Just as there are motorcyclists, and bikers, there are bicyclists, and roadie scum.
Yes, we share the road. Bikes are supposed to follow all the same vehicle codes we do, however, if they can't keep up with traffic speed, they fall under the slow vehicle clauses, (like farm equipment, horse drawn carts, etc), and should keep to the right to allow other traffic to pass safely.
Now, roadies scum are easily identified by their lack of respect for larger, faster traffic and refusal to get the hell out of the road. They tend to ride down the center of the road, often in multiples, despite their speed being well below the flow of normal traffic. They defend their tactics as attempts to be 'visible' rather than staying to the right where slower traffic is required to be, by law.
Do not judge by spandex alone! Commuters will also be wearing spandex, but can be identified by having high quality lighting. Much like LD riders and their Aux lights, the commuters ride day and night and have serious lighting, not some battery powered blinkie. Commuters will be blowing by the roadie scum, but stopping for the red lights and stop signs, though often track standing rather than putting a foot down. They obey the traffic laws, but will pass stopped traffic on the right when possible to maintain momentum. 'Mo' is big juju. Maintaining Mo when you can keeps energy output even and flowing.
Feel free to bounce check roadie scum into the weeds. Inform them as you pass that we SHARE THE ROAD, which does not mean that they get to ride down the middle of it at 15 mph in a 55 mph zone.