Ranked Choice is a fouking abomination. It needs to go
What's wrong with it? It gives power to third parties and allows people to state their preferences better.
I'm happy that Golden won, but RCV does not actually give power to third parties. It just appeases people who insist on voting for unelectable third parties. If, say, a left-wing third party actually managed to get more votes than the Democrat, it could result in Republicans winning.
The the scenario you describe, the most likely result would be the left-wing third party winning (unless the party was so extreme that most Democrats preferred the Republican, in which case it seems unlikely the third-party would beat the Democrat in the first place). Which just proves that RCV does empower third parties.
I think his point is this. Lets say there was an election with these first round results:
Democrat 400
Republican 300
Left Wing Third Party 420
Scattered 20
Under FPTP the left wing third party would win. But after the scattered votes and the Republican are eliminated, you could end up with a result like this:
Democrat 650
Left Wing Third Party 450
With the rest being exhausted.
Something like that kind of happened in a Minneapolis city council election last year. A Socialist Alternative candidate led on first prefs against two Democrats (Republicans aren't a serious party in Minneapolis politics), a progressive one and a more moderate "establishment" one. The moderate came in third and was eliminated, but most of his votes flowed to the other Democrat, thus allowing them to win.
Granted this assumes that most of the Republicans back the Democrat on lower prefs instead of backing the third party out of spite or just letting their votes exhaust. Its a different situation than that City Council election where the other candidates were both Democrats.