I don't think I'm sounding hysterical, but tone doesn't carry well through writing so I'll respect that. Also, I'm deliberately not calling you names, and you shouldn't call me names. It isn't SJW garbage, because I've actually stated the argument as relates to my point instead of lumping my argument in with some incorporated reference.
You claimed my position "dehumanized" and "othered" you, which is ridiculous. (Frankly, in 2016, people who refuse to sit next to a woman, or a menstruating woman, have "othered" themselves.)
My answer to your question is he should not be able to as a right, but the other people should respect his request to the extent it does not extremely inconvenience them. For example, I don't think anyone should feel compelled to not sit next to their spouse to accommodate. What I don't agree with is the people who say that he's wrong to even ask and who say no as a matter of principle or because they don't care at all.
Changing from an aisle seat to a middle seat, on a full flight, is an "extreme inconvenience," especially for a full flight from Tel Aviv to New York, or something like that. Likewise, a 30- or 60-minute departure delay for a full flight after someone deplanes is an inconvenience.