You're right: on one hand the author pointed out a fact. OTOH, he wrote that this sexist assumptions are somehow valid.

He seems taking pride in what is called "the hero complex": being proud about sacrificing oneself for others' benefit (like a soldier fighting for his country).

IMO, while one is free to spend his life the way one prefers, I agree with you (and disagree with the author): this should not be encouraged. And I absolutely agree that my life is not worth less than a woman's.

Hence, I correct my point: I agree with the author base statement ("Men are considered expendable"), but not with some of his conclusions. But I still think that talking about men's "expendability" raises the awareness about the issue, so it's positive.