FairVote is invested in Instant-Runoff Voting and won't consider promoting any other system, so they have to make excuses for its failures. Their excuses aren't valid or convincing.

1. They like to talk about IRV “often” electing Condorcet winners in real-world elections, but literally any voting system will often elect the Condorcet winner in a two-party system. The goal of voting reform advocates like me is to end the two-party system, not perpetuate it.
2. Less complication is a good quality, but better voting systems like Approval, Balanced Approval, STAR, etc. are also less complicated than IRV, so that’s not a very good reason to choose it over them.
3. It is hard to vote strategically under IRV, but that’s a consequence of being such a flawed system. It’s not likely to elect the most-representative candidate when voters are honest, and it’s not likely when voters are dishonest, either. Increasing your support for a candidate can help them or hurt them. The population changing ideology away from a candidate can hurt them or help them. When there are multiple strong candidates, IRV behaves illogically and chooses a winner essentially at random, making it difficult to predict whether your strategy will backfire or not. But that’s because of a flaw, not a feature.

They have another more recent page here: Why the Condorcet criterion is less important than it seems, which has its own share of invalid arguments:

If there is a Condorcet winner, it means that he or she is preferred to every other candidate — not necessarily liked more than other candidates

This is true, but IRV doesn’t elect the most-liked candidate, either, so it’s not an argument in favor of IRV.

Condorcet winners are centrist by nature, regardless of the preferences of the electorate.

This is a nonsensical statement. Condorcet winners are centrist by nature, relative to the preferences of the electorate. If the population moves right, the Condorcet winner moves with them. If the voting population is the Communist Party of America, then the Condorcet winner will be a good representative of the typical Communist, not a centrist on a worldwide political spectrum.

Agreeing that the Condorcet criterion is desirable is equivalent to saying that moderate candidates should always win.

Again this is “moderate” relative to the voters. So yes, the only desirable goal of a voting system is to elect the best representative of the will of the voters. Condorcet systems are much more likely to do this than IRV is.

Any election system that favors extremists would be considered unreasonable

Correct, and IRV favors extremists, so it is not a reasonable voting system.

the same rationale must be applied to moderates.

Incorrect, as above. “Moderate” in this context means “the best representative of the voters”. A good voting system should favor the best representative. It should not elect unrepresentative extremists at random because there are too many good representatives crowded together in the center.

Like most voting reform enthusiasts, I started out as an IRV promoter and FairVote supporter, but as I learned more, I realized it is a poor system and should not be adopted. Unfortunately, their marketing power is much stronger than ours, and for every person we successfully convince to stop supporting IRV, FairVote’s marketing convinces another dozen low-information voters to support it. Fighting their misinformation is a never-ending uphill battle.