First past the post is good for no one

There can only be two possible reasons to reject proportional representation in favour of fptp. We can either be of the opinion that (unaccountable) government is good (so we do not want it threatened by democracy) or alternatively we can hold the view that democracy strengthens government and that without democracy to constrain it there would be less government. In the context of choosing between fptp and pr we cannot claim that democracy enhances government because the alternative to pr is not anarchy it is fptp (and fptp does not destroy the government). Fptp is not anarchy so we cannot claim that to reject pr means that there is no government... democracy always provides accountability and reduces government. Since using a fptp system voters still must choose which party they want to win this means that the left can win. Reducing the choice available to simply two parties doesn't encourage liberals to support the Tories. Since (centrist) voters are not coerced into supporting the Tories with a two-party system then fptp can only offend liberal voters which is to the detriment of freedom or be neutral. If voters are generally leftist (and democracy leads to big government) then fptp ensures a Labour victory. If democracy is not synonymous with government then it reduces the government and the only reason to reject it is if we support the Labour party or equivalent.

First past the post can only be harmful because people are not compelled to vote for the Tories in a two party system and it is likely that they will let Labour win. If the people are socialist then fptp will result in a Labour victory and if they are not then we would want to have the most democratic system possible to enable the people to free themselves.

Democracy can never impose freedom on the people... any restriction of choice will lead to bad outcomes because intelligent people are less likely to be willing to be (electorally) coerced into voting tactically so we lose intelligent votes. Nothing can prevent a socialist electorate getting socialism (not even fptp) but forcing liberals to choose between two bad options is harmful. Intelligent people can see that fptp is harmful if the people are liberal but it is not intelligent people who are in control by definition.