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.
But thanks for your “help”.