It presents a thought experiment that is contrived to be free of any game-theoretic concerns, and then this example is used as a rhetorical sleight of hand by positing a superficial analogy with a real-life example, in which the game-theoretic concerns are of supreme importance.

That doesn't seem fair. Yvain explicitly points out that the salmon example is different precisely in that it doesn't have the same game-theoretic issues. From the OP:

The British salmon example, on the other hand, was designed to avoid the idea of "offense" and trigger consequentialist notions of harm minimization.

The example specifically refers to the displeasure that salmon cause the British as "psychic pain", priming ideas about whether it is acceptable to cause pain to another person. The British are described as politely asking us to avoid salmon photography as a favor to them, putting themselves in a low status position rather than demanding we respect their status. British are white and first world, so it's hard to think of this as a political correctness issue and wade into that particular quagmire. And because the whole salmon problem is the result of an alien prankster, there's no easily available narrative in which the British are at fault.

So, Yvain isn't making a "superficial analogy". He is highlighting precisely the differences that concern you, because they are part of his point.

You continue:

Well, yes, but the whole point is that people's sincerely felt emotions are very much directed by their brains' game-theoretic assessment of the situation, which may well indicate that a seemingly irrational extreme emotional response is in fact quite rational given the circumstances.

It is important to keep these issues in mind, and I agree that Yvain downplays this possibility in the OP. But, in fairness, you seem to ignore the fact that your remark applies just as well to those who find themselves sincerely offended by Muslim demands not to draw Mohammed. They too should recognize that their offense is "very much directed by their brains' game-theoretic assessment of the situation, which may well indicate that a seemingly irrational extreme emotional response is in fact quite rational given the circumstances". And they should recognize that what that part of their brain considers to be rational may not really be rational in light of all of their goals.

Great counter-argument; perhaps you should post your own analysis of the offensiveness question.