Americans may not know that most countries don't have public primaries the way that the US does - here in NZ it varies from party to party - at one extreme the Greens hold a very public transparent democratic process, at the other the National party use closed 'smoke filled' rooms

I'd guess that most people don't know the detailed rules of elections in other countries.

With that argument China is also a democracy, since you can vote who will get to run the party. I'd argue that a proper democracy requires new parties to be easily formed and quickly gain momentum and power if they have support from a fraction of the population. I don't think that ranked choices allows for that, as even if the third party "Greens" in this case got 25% of the votes they'd get thrown away in favour of peoples secondary choice.

Minor nit: I believe only party members vote on party leadership, and it's actually difficult to get into the party. Also, I'm under the impression that the voting is multi-tiered, where you vote on your level and region on which member gets elevated to the next level.

It's actually an interesting system, and as usual, it seems adding indirection solves some problems while introducing others.

I don't know how you got from my comment to China. I speculated that ranked choice might have more of an impact on which candidates are selected in primary elections. If you think voting for who will be the party's candidate is undemocratic then we're already there, that's already how it works, and I don't see anything in my comment that would lead to a single-party system like China. Maybe you could elaborate on why you think ranked choice in primary elections would take us to a single party system.

What I don't understand is why you think 3rd parties should rapidly gain power if they only have support from a fraction of the population. Why should their power be disproportionately larger than the # of people supporting them? I don't think it's very democratic to have a candidate with only 25% of the vote win the election.

I mean... are you suggesting that some system where someone could get elected with only 25% of the vote would somehow be more democratic? If a party or candidate can only get 25% of the vote in an election for a single position, like mayor, they aren't going to get elected, that's just democracy, right?

RCV makes it more likely a third party could get 50% of the vote though, since people can vote for it without worrying about "throwing their vote away", or throwing the election to a right-wing party when they want to vote for the lesser left-wing party.

I think once people see that their 'other party' preferences are at least being represented in the early rounds, they will gain confidence in their ability to express their actual desires in the ranking. The understanding that third parties actually have a real chance if they get enough voters' first choices will wake up the Ds and Rs that they can't just coast and hand wave anymore or they'll get tossed out.

Yes if this voting style extended to primaries or other elections with multiple candidates from one party, it also has benefits. You can vote for the less popular candidate that better suits you, while falling back to the popular one you're willing to settle for. Preferences are generally reported, so people will see 'unpopular' options actually getting votes and things shift over time.