The reason is that, historically, IO9 readers and commenters are open to the idea that “gender” is not synonymous with “sex parts”. We are welcoming of science fiction that pushes the boundaries of what it means to be a man or a woman, or even other expressions of gender. We applaud the creative output (books, movies, etc.) of all people, across the gender and sexual spectrums. We welcome everyone, and we accept their private decisions on how they express their gender and sexuality.
All it took, with the above article, was for someone in the comments to correctly point out that chemical analysis of a fingerprint can establish the biological sex of a person (how they were born) not their gender (how they choose to live) and the phobics came pouring out of the woodwork. I have to believe that some of my favorite IO9 writers, editors and commenters share my concerns, and at minimum (even if they disagree on the gender/sex issue) that they have enough respect for their fellow readers and writers to keep objections to themselves.
Then again, maybe this is just another time I’m sticking my foot in my mouth.
Edit to add: I come across above as painting all of the commenters at Gizmodo with a broad brush. That has to be wrong. There are many bright people commenting there (heck, I comment there, as do many of you reading this). What I fear is what I perceive to be a “louder” troll element and a quicker tendency for discussions to deteriorate into arguments.