The two longest lasting, largest, most successful democracies of all time - I don't see the problem.
The arguments against winner-take-all are mathematically maximizing a collective total happiness score for single elections. But governments are run by people, not math, and I've yet to see anything addressing the psychology of election systems and especially not over time.
If instead election systems are scored on how well they do after 250 years or how few world wars they start then winner take all is the only winner.
They both have problems with large minorities of voters not being represented in their respective parliaments.
It's hard to argue against someone's feelings.
But if you want to talk about good governance over time, does the country endure and does it make good decisions that ultimately benefit the country, that would be a more productive discussion. You have an uphill battle, with history not being kind to proportional democracies, but there's plenty of room for opinions and reasonable disagreement.
It's possible that constantly pitting constituents against each other is actually a vital component of democracy.
Granted, quadratic voting specifically was probably not designed with parliamentary elections in mind. There are other systems in use that are designed to be fair and result in decent representation of voters.