Okay, let's ignore the most powerful nation in the world from our discussion. Shall we do this for all future discussions too or is it just this particular discussion that you want to ignore America?
It depends what you count as neo-Nazi. If you're talking specifically about parties that identify as neo-Nazi parties then there are almost certainly far fewer neo-Nazi party members in Europe than there are libertarian party members in Europe. Let's take the UK, since you started off with it. Neo-Nazi Party members in the UK: 0. Libertarian Party members: 500.
It's also nice that you have conveniently left out UKIP,
which states in its constitution:
"2.5 The Party is a democratic, libertarian Party". UKIP currently has 30,000 members and
won 23% of the popular vote in the most recent UK elections.
Furthermore, if you are widening it to include parties that do not explicitly identify as neo-Nazi but that neo-Nazis probably vote for and agree with, such as the BNP, PVV, FN, Golden Dawn, etc, then it would be hard to deny that Marine Le Pen or Geert Wilders are fantastic at marketing their parties. Nick Griffen sucks at marketing, but there are plenty of examples of far right parties in Europe who are exceptionally skilled at marketing their party as the solution to all our problems, as the party that's not afraid to say what everyone's thinking. I am sure that Marine Le Pen would have made an excellent marketing consultant in another life. Marine Le Pen was a lawyer and Geert Wilders a speech-writer before they entered politics for themselves. Do you think that these two people would be bad at advancing arguments and convincing people of their views, however reprehensible? A lawyer and a speech-writer?
So yes, if we ignore the biggest country in the Western world, and if we ignore the biggest libertarian party in the UK, and if we ignore the outrageously successful marketing of the biggest far right parties in France, NL and Greece, then maybe, just maybe, your point about libertarians suffering from poor marketing might be able to stand. Notwithstanding the fact that you haven't presented any actual positive evidence for that, but rather just said "oh look at the amazing ideas we have! we would be so much more successful if we weren't also associated with truly terrible ideas!"