I drive a car now and then in Cambridge and Boston, and I have to be constantly on a lookout for misbehaving cyclists. It's like most of cyclists are not even familiar with basic traffic regulations. If I was not paying extra attention, and was simply following traffic regulations on my end, I would be involved in more that a few car/bicycle accident.
Cyclists will often ride between rows of cars that are stopped at a traffic light in an effort to get to the front, probably assuming that the 3 feet law doesn't apply in that case.
Cyclists don't have to be toxic for the whole setup to not work, they just have to not obey the same laws that are in place for cars. Where I live, I'm more likely to be hit by a cyclist on a pedestrian crossing than by a car.