Proportional voting accelerates freedom because it gives voters more choice

If there is only one winner in a constituency seat then people will feel constrained to vote for one of the leading parties, be it of the left or right. This means that minority parties are excluded as people do not want to risk wasting their vote.

The advantage of enabling minority parties to do well is that it makes it possible (for voters) to enforce their core beliefs without imposing extraneous violations of liberty which they do not support. A voter that is illiberal in a particular area is able to be liberal in all others, provided they get their particular wishes enforced, or at least represented, they are not compelled to support a collection of prejudices, only their own.

We use the Government to make laws, to compel and prevent certain actions. If we can do this with precision, allowing all other freedoms where possible then this leads to more freedom and a smaller State. Excluding minority parties, as with existing voting systems, which are not proportional, reduces freedom because we have no choice but to support a party that is tyrannical in ways which we do not like.