First past the post is a crime

Governments are always proportional and to have a government elected by any less democratic means is a crime. So to use the first-past-the-post system to elect a government is a crime because the government elected will be illegitimate. (Governments without legitimacy are criminal.) The only valid system of democracy and by extension government is one where the voters have a true choice and are represented by someone who reflects their views. Only direct democracy is valid and proportional representation is a form of direct democracy because the representatives are very closely aligned to the voters. There is more choice with pr and so the views of the voters will be properly reflected by the chosen politician. People who advocate fptp are advocating a crime.

Pr is a natural right if there are more than two people

Since we are not alone in the world and other people exist then it is natural to have a government and further it is natural to have a democracy. No state can be valid if it does not have a mandate from the people which is derived from democracy. All states must be democratic and if there are more than two people in the world then it is a requirement to have a state... otherwise property rights will be determined by force alone.

If there are only two people then it can be assumed that each will vote for themselves and there is no need for (government and) democracy. It is when there are more than two people that a state can be valid and the majority can protect themselves from the aggression of the minority.

If there are more than two people it is natural and preferable to have a democratic government so that property rights are determined by consensus and not theft. It is a natural right to form a government if it is democratic and by extension full democracy is a natural right. (We have no right to form a state without democracy.) We do not have full democracy if we must vote tactically as with first-past-the-post and so pr is a natural right. Proportional representation is a natural right because whilst we have a right to form a democratic government we do not have a right to oppress democracy. Since we do not have a right to oppress democracy (and yet we have a right to form a government) then pr is a natural right.

None of the above is inconsistent with the non-aggression principle.

First past the post is torture

We can define torture in this context to mean harm imposed on someone by the state for no reason. It is different from the normal execution of justice. Torture by the government is imposed arbitrarily.

First past the post is a form of torture because it fails to grant us the full expression of our political views in a democracy. There is no reason to stifle democracy and so then we should have the most democratic system possible. To reduce democracy is to reduce the freedom of the people in favour of the state and since there is no reason to do this (and a lack of freedom is punishment) we conclude that fptp is torture.

Tyrannical statists don't like democracy

If the majority of people want peace then the elected government will reflect this and those who want aggression will be powerless against the government. If most people want war then (elected) government will be bad but then so too will anarchy be bad. Democracy is always an improvement on its absence.

Clearly proportional representation is more 'democratic' than first past the post because the voters are not motivated to vote tactically. Pr is like having direct democracy for each issue because the voters are able to be represented by someone who very closely matches their views. If we concede that pr is more democratic than first past the post then it is more like (legitimate) government than fptp which then is more like anarchy. But since democratic government is always better than anarchy (for reasons given above) then pr is always preferable to fptp. Pr is better than fptp for the same reasons that elected government (and democracy) is better than anarchy. (If democracy (the ability to refuse government) is not better than anarchy then there might be arguments for fptp over pr.) Only someone wanting to use the government for unpopular and illiberal reasons would object to more democracy. If people want a government there will be one so the best approach to prevent tyranny is to make sure that those who oppose the government are powerful which means to have the most democratic system possible. People neglected by a lack of democracy are always dissidents of the government... only (tyrannical) loyalists to the state want less democracy.

People want to be free

Few governments claim that their actions are intentionally malicious so then we can deduce that all of the crimes committed by governments have been done in the name of communism and socialism. The government is synonymous with socialism. The purpose of democracy is to reduce the size of the state so then democracy is antagonistic to the government and to communism. Democracy is bad for communism and socialism because it enables the people to have a veto on what is being done in their name and (purportedly) for their interests. The government will always claim to be socialist and acting for the good of the people and the 'country' so then even if it is actively engaged in the extermination of the population this will be defended by the government on the grounds of socialism. Democracy is the only protection available to the people against this kind of socialism. Since pr is more democratic than fptp we can say that pr reduces socialism much more than fptp. Pr is bad for socialism. If voters are forced to choose the least bad of just two political parties then they have been given less democracy (and less protection from socialism) than with pr.

First past the post anarchists lack empathy

Anarchists do not want a government so it is more difficult for them to differentiate between different forms of tyranny and they will be less sensitive to pleas for a more lenient government... perhaps interpreting these as advocacy for the government. For example someone who wants democracy instead of dictatorship is clearly someone who dislikes the present government and can be thought of as a liberal. But the anarchist (unless they are sympathetic to the claims of the democrat) might be deaf to the desire for democracy over tyranny because they want neither. An empathetic anarchist might be sympathetic to the desires of the democrat and might even advocate democracy in these circumstances despite being an anarchist... since to get some freedom from the state now is better than none even if it is not full anarchy. To advocate (more) democracy is not to advocate the state and so anarchists might advocate (for example) proportional representation over first past the post. An unempathic anarchist might well be indifferent between pr and fptp merely because they cannot see things from the point of view of the democratic rebel. It is consistent for anarchists to prefer pr over fptp but it is perfectly possible for a genuine anarchist not to be able to see that pr is preferable (since they are not able to empathise with the reformers). If anarchists have no empathy it is possible that they will not be able to see how pr is better than fptp.

First past the post is authoritarian

With a proportional voting system voters are able to put much more 'information' into the system. They are better able to express what they like and don't like. They are better able to expose the government (and as a consequence everyone) to the reality of their opinions. With fptp reality is delayed because the two-party system makes it easy for the state to ignore its voters. With pr the state must be much more responsive to the people. Since reality is inherently libertarian and people want to be left alone more than they want to be protected more democracy will lead to more freedom. First past the post suppresses freedom because it enables the state to assume authority where it is not wanted. Proportional representation makes it easier for the people to reject the government. Coercion and authoritarianism are bad so if people are better able to reject these things this is good. A lack of democracy makes bad things easier (and freedom less likely).