I think alot of people outside of the motorcycling world, and from some of these anecdotes even within the realm of motorcycles, consider anyone with a bike, jacket, and helmet to be a 'biker'. In some cases, I think it is simple naivete of the speaker, not knowing that in may circumstances, many people recognize that there is a difference between the two, often of considerable proportions. For others, I think the "what's in a name" notion applies, and they don't feel that there is a need to fit to one label or another.
I heard an interesting story on the radio a little while ago, concerning race and a bunch of kids from urban schools, and how the perception and importance of race is changing in the next generation or two. When interviewed, the kids - would not self identify themselves as "black", "white", Asian, Native American, etc. regardless of their physical attributes. They all simply said that they were of mixed race, and they were fine with that, without having to self identify with a particular genotype. They became quite perplexed when they were made to choose and check off just one box in a medical form that was to specify their race, where I would suspect that many of us older folks would simply have checked one without thinking about it. All of these kids, selected "Other", and rejected the notion of having to self identify as a specific genotype/label. From the mouths of "babes", such as these, we all may learn something, I think.