ah libertarianism, the most epic and intelligent position that nobody has heard before
This is fair tbh BUT I do pretty much never say that I'm libertarian, partly because of the connotation that you describe (same with atheist), partly because I prefer saying "conservative" and trying to change that word back to its actual meaning. I do identify as libertarian and I would say so if you asked me, but I would never exclaim it.
If I have a position or opinion or something I would never say "____ because I'm libertarian", for example. I also wouldn't say cliches like "____ because that's not the role of government" or "that violates the NAP", unless I was specifically talking with other libertarians. There's just way better ways to phrase things to sidestep people's preconceived notions and be more persuasive.