You have to care to a certain extent when you are out on the road because someone in a car could kill or injure you.
However, JoeyBike's point is one that I have argued many times which is: drivers' opinions on the lawlessness of cyclists are wildly inaccurate and not the least bit objective, and are ultimately irrelevant to discussion of cyclist safety, and only meant as a distraction from the actual threat that drivers pose to cyclists and pedestrians.