Such offended surprise is disingenuous for the following three reasons:
1. Post-Arthur Conan Doyle (who is likely turning over in his grave, as much because nobody remembers anything else he wrote as for the assumptions that modern viewers make about his characters), Holmes and Watson have gained an edge of sexual tension--whether we are dealing with a man and woman or two men--hence Rowan Atkinson's outrage in Thin, Blue Line:
In more recent movies and shows, the homoerotic element is both more obvious and more unself-conscious. BBC Sherlock takes a modern approach; affection between the male characters is not perceived as automatically loaded (i.e., in need of repression). Nevertheless, for many years now Holmes and Watson have represented that all-encompassing male comradely which attracts women to yaoi manga.
2. If producers will go around casting Jonny Lee Miller and Lucy Liu as co-stars, they should accept that disclaiming an interest in producing sexual tension = instant rolling of eyes. Really? Have you seen them? Really??
3. Much like the Buffy writers who created a workable romance between Buffy and Spike and then started getting defensive about viewers wanting more, the writers and directors of Elementary have, for lack of a better word, already Freudianized the characters' relationship.
Sherlock has a tendency to barge into Joan's room in the mornings, while she is still asleep or just waking up. In a Season 1 episode, in one of my favorite scenes, Holmes comes in and sits down in a chair facing the bed. He sits with his legs spread. Watson turns over to face him, curling her hands under her cheek.
Everything about the scene screams physical and emotional intimacy. It isn't overemphasized. In fact, it is played to a fine degree of mellowness. But it isn't remotely platonic. Miller's posture demonstrates alpha-male sexual confidence while Lucy Liu is luminous.
It is possible, I suppose, for television producers to be completely clueless about the importance of visuals. Still, it's gotta make you wonder how these people get their jobs.
The producers claim that they want to avoid the "Moonlighting trap" (as one article puts it). However, I think Moonlighting is no longer a proper analogy for the romance-that-kills-the-show (do producers watch nothing later than the 1980's?). Several recent shows have done a more than respectable job bringing the leads together without destroying the show's content or trajectory.
Writers are better than they used to be! (It takes skill to continue to make an ongoing, non-dysfunctional relationship interesting, but it is possible.)
"You're my work wife!" Castle tells Beckett in an early season. He has a point.