Interesting, I view ranked Choice voting as diversifying the candidate pool. I expect this would increase third party voting not decrease it

Ranked-choice voting does exactly as you say, increasing the diversity of candidates (because no vote is ever "wasted").

It also completely blocks extremists. They are ranked first by their supporters but last by every single other voter. This effect is mostly visible in a 3+ party system though.

Wow:

https://reason.com/2022/04/28/florida-tennessee-ban-ranked-c...

This is naked anti-democratic power-mongering. The only reason to ban it outright (rather than, say, letting people try it and switch back if they find it "confusing") is because you're afraid that people might get the hang of it and think it should be used for state and national elections as well.

Their official reason (for banning RCV) is that it is too confusing for voters.

So what do I know, I'm just a moron..?

...thanks for the great Reason/link.

Voters do find it confusing. Not all of them, but enough that it matters. E.g.: In San Francisco, Chesa Boudin only won as District Attorney in the final stage of the final vote count because his supporters were more likely to know about and use RCV than moderate, conservative, and/or low-information voters.

1. How much of that is due to its inherent complexity, and how much is just due to its novelty? If they had grown up in a society where RCV was the default, how many of those people would still have been confused?

2. People misunderstand that FPTP requires tactical voting as well; are the number of people who will continue to misunderstand RCV if it were to become common higher than the number of people who currently misunderstand FPTP?

Consider that anyone who suggests you to vote third party to "end the two-party system", before the voting system has changed, fundamentally misunderstands how FPTP works as well.