You actually haven't solved the problem. This is what one might call the naturalistic fallacy. "Damage" is a value judgement you attach. His brain has been altered from the human baseline. So what? If my brain was altered and I got perfect memory you wouldn't make the claim that I was "damaged". My brain is altered daily by outside forces. God knows how the chemicals and actions coming from other bodies have affected and changed me. What made me love this person? Their pheromones or a precise chain of events?Well no, his passions are wrong because his brain has been damaged by an outside force.
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Essentially you're going:"I have certain base emotions, my base emotions are the measure of all things, those who don't share my base emotions are thus damaged and thus are not thinking correctly" when, in fact, your baseline emotions are also just the result of similar physical phenomena and the values you attach are a result of said emotions.
It's all "outside forces" man.
Hence, privileging your own passions that are just as much a result of processes beyond your control. Exactly as I said.
It's a challenge to his position and one he should consider. I'm not for brainwashing but I've not been satisfied on this point so it should be explored (if it turns out that I can't ever be satisfied then...well, brainwashing it is) .But apparently you're a person who thinks brainwashing is totes fine as long as society benefits, so I'm not sure we will ever be able to agree on any moral question
You seem to find it difficult to deal with arguments that in some way trigger your moral intuitions. This is the second time this has happened, to my knowledge.
Perhaps you should consider that we're not all the same way. Or perhaps you should kinda not be surprised.