Advocates of Proportional Representation are at the mercy of the politicians

In a FPtP election, each constituency will generally have only one candidate from each of the main parties. If the FPtP system allows individual politicians to prosper, as is often claimed, then why not offer more than one candidate from each party? The immediate answer is that by doing so the party would be hurting its chances by splitting the vote.

To promote more than one candidate would be sacrificing the power held by the party.

We vote along party lines because that is our expectation of how they will vote, in Parliament. It is (largely) irrelevant whether the local candidate is good or not, what matters is which party they are from. We are not selecting our representatives to be thoughtful arbiters of the law, instead to be partisan, tribal weight to our cause. If it is the number of votes cast that will count, and not the merits of the particular case, then we can expect people to be 'tribal' and to ignore the individual merits of each candidate.

If crime is possible, as in the case of (aggressive) taxation then what matters is not the good judgement of our politicians, but what side they are on. Politics is reduced to an opinion poll, a measure of the weight of opinion, a popularity contest and not a process to deduce the correct way for the country to be Governed. So then, who cares about the merits of the individual candidates? That is not relevant...

Someone that wants to commit a crime might not want to be represented by a saint, or a scholar. The result is that (reasonable) people will vote for the Socialist party to avoid the ignorance of a politician that values strong Government and yet does not want high Government spending. It's hard to understand why someone who wants low taxes would be prepared to defend the other prejudices held in the opposition (to the Socialists) party, in a FPtP system. FPtP means that the 'right' is often represented by people with other prejudices instead, or at least they can get a purchase in the process because people who want economic freedom have no other choice. The desire for economic freedom is hijacked by Social authoritarians, even (collective) Nationalists.

If people such as these, with such prejudices, exploit the undemocratic FPtP system, why would they want for it to be replaced, since it gives them their opportunity to punish Social liberals?

We allow (tolerate) this because we are powerless to prevent it.