don't be ashamed about it. i'm proud to say i'm agnostic, just as people tell me they are proud to believe.
How many of you notice that you normally don't introduce yourself to a neighbor or a co-worker, and as soon as possible, you announce that you are an atheist. Believers do it much of the time. They announce to as many as people as possible that they are christian. Once someone gives me the challenge, I have no problem promoting atheism as a positive lifestyle, as well as a complete separation between church and state.
Nope, never experienced that but I get what you're saying.
I personally don't make any actual effort to promote being an atheist. I think that a big part of being an atheist is the mental comfort of not needing to proselytise to reinforce your own belief system.