Are you really confused about what I meant (the type of extreme free-market politics advocated by figures like Ron Paul or Penn Jillette -- incidentally the latter is a prominent atheist) or are you just being a pedant for the sake of it?
Well, not being familiar with /r/atheism, I wasn't sure if you actually meant what you said and we're drawing an invalid conclusion based on the popular portrayal of libertarians (at least in the US) as anti-bear, or if you meant specifically right-libertarians.
Had I been familiar with /r/atheism, I might have been able to guess which of those was correct.
For future reference, when people say "libertarian" without further clarification, at least in American politics, they almost always mean right-libertarian.
IME, the split is much closer than you suggest between people meaning right-libertarian and not realizing there are more and meaning libertarian more generally, but perhaps associating that with opposition to the left (exluding the use of “Libertarian”—capital “L” in writing, at least when not sloppy—to mean “member of the Libertarian Party", which itself leans right—but not exclusively, I've met left-libertarians who are in the LP.)
You think half of users of the word not realizing it doesn't exclusively mean right-libertarianism is an argument against interpreting unqualified use of the term in that way? That's not how I see it.