>my motorcycle is highly important to me and a fundamental part of who
>I am but I don't introduce myself as "I'm Steve the motorcyclist".
You might, if fundamental meant: "you had to ride that motorcycle" yet you were being told it made you unwelcome anyway and you were still trying to define your identity and your place in the world. Then, you might very well say, "Hi I'm Steve the motorcyclist, I won't be at the movie theater tonight because they don't allow motorcycles on their property", or: "I'm Steve, the motorcyclist, I can't visit that other state/country/province because they don't allow motorcycles on their roads." You'd be even more likely to say: "I'm Steve the motorcyclist" if you did go to the movies or that other state, because then you'd be protesting the injustice by going anyway and what's the point if everyone there thought you arrived in a car.
Besides, you're doing a disservice to those motorcyclists who've gone before you. At one time, wearing leathers and sporting a pony tail was enough to land you in jail all by itself. How is this any different? Maybe you wouldn't be riding your bike now if it wasn't for all those hippie freaks flying their flags 40 years ago. And maybe (if people like this girl "keep on keepin' on") homosexuals 40 years from now will be forgetting how controversial it was once to be one and will be chastising someone else for wearing their identity on their sleeve.