In its more than 100 years of history for most of the time the motorbike has been just a mode of transportation. Once the automobil got cheap enough for (nearly) everyone the motorbike has become a "recreational vehicle" (not in the sense of a RV) or a symbol for a certain lifestyle. Especially the motorbike as symbol has often lead to certain discriminations against bikers - in my experience in the USA more so than in Europe.