This isn't just about you. If it were, you wouldn't have a chance. Gays have the same problems with some of our more colorful brethren. However, the gay rights movement was not started by people who look like me. It was started by drag queens rioting when they got fed up with police harassment.
People have the right to be themselves.
The marijuana reform movement can learn a lot from the gay rights movement. On the other hand, if you are not a marijuana user and you are just coming out as an anti-prohibitionist, then say that you are not a user. This will actually add credibility to your statements, even though logically it should not. Former smokers are the most pathetic of this group. They have the knowledge, and credibility, and no risk at all.