My first reaction to this was "is this a guest post by Robin Hanson under Yvain's name, to see if anyone notices?"

You could argue Brits did not choose to have their abnormal sensitivity to salmon while Muslims might be considered to be choosing their sensitivity to Mohammed. But this requires a libertarian free will.

Well, no it doesn't. Muslims observably do make a choice in the matter (as proved by the fact that they discuss it and take different views). (Link.) To equate this with aliens hard-wiring our brains to graft on an arbitrary offense-trigger is plain no-free-will determinism, whereby the past reaches past the present to cause the future, just as the alien reaches past our internal functions to cause offense-taking at an arbitrary stimulus.