First past the post is not libertarian

If we consider the case of either direct democracy or proportional representation then we can see that the interests of the public are served in both cases. An example of direct democracy is a referendum where the people (however well-informed or otherwise) vote directly on the legislation without a representative voting on their behalf. We can consider proportional representation (despite its name) to be a kind of democracy without representation because voters are truly represented by someone who shares their views; in a representative system like first-past-the-post the views of the representative often differ from the voters.

Because, by their nature, officials elected via fptp are close to the government (unlike with proportional systems) they will tend to vote in favour of the state in contrast to the people. The people (or proportionally-elected representatives) can be relied upon to vote for their own interests ahead of those of the state, which is what we would expect in a democracy. Since to advance the interests of the people ahead of the state is libertarian by definition then we can say that true democracy is libertarian and that fptp is not libertarian.

Libertarian policies will be those which are more favourable to the people of a country than the state so then (because democracy serves the people) we can say that true democracy is libertarian, in contrast to fptp. Because first-past-the-post is representative and not direct it is less libertarian than other systems.