Re: Nope, COVID-19 is not a catch-all excuse for backdoor deals
So there's two elements to its lack of proportionality. So there's the historical evidence it would produce less proportional results for the distributions of votes we see in typical British postwar elections. There's an argument to be had that this wouldn't hold up in reality because people would change their way of voting under the new system, but the fact we don't see radically different results in elections that do use a form of PR (e.g. London, EU, Scotland etc) vs the FPTP general puts that under doubt.
This is rooted in the second element: the fact that AV to all intents and purposes raises the victory threshold from a plurality to a majority. This has the effect of making the electoral results more representative of the actual views of any given individual constituency, but perhaps counter-intuitively makes the elected parliament as a whole less representative of the views of the country as a whole.
You can put this in some other terms, for example it is often put that an elector may vote for a candidate without worrying about wasting their vote. This isn't true at all, because unless your first-preference candidate wins, your first preference view is fully discarded. If none of your preferences win your views, as with FPTP, don't count. AV just gives you more ways to express views that are just as easily crowded out by a single, large party: AV would make landslides victories even bigger than under FPTP.
But don't just take it from me: https://www.electoral-reform.org.uk/voting-systems/types-of-voting-system/alternative-vote/
Biting the hand that feeds IT
