Why didn't Sherlock see through Molly's disguise in TAB?

 (Sherlock meta by penfairy)

I’m seeing some people say that it’s unrealistic for Sherlock not to see through Molly Hooper’s disguise in The Abominable Bride, but remember that this is all in his mind. Sherlock is seeing what’s appropriate for him to see.

Since they recreated the scene where Sherlock flagellates the corpse, I expected them to introduce Molly in the same scene. But they didn’t, because in Sherlock’s worldview Molly did not exist in that scene. She was too unimportant to take any real notice of. Later on, she’s introduced to us as Hooper, and she’s effectively neutered by her male disguise, rendered sexless. She is nothing but the slightly argumentative doctor who provides valuable assistance with his work. “I don’t count” is her famous line in S2, and it takes Sherlock some time to realise “You do count. You’ve always counted and I’ve always trusted you.” He didn’t see the real her and who she truly was until much later on, just as he doesn’t in the special. That is why it’s such a shock when she doffs her disguise and he sees her as a woman, and why one of the biggest revelations he has in his mind palace is “I’ve treated the women in my life horrendously and I need to make amends.”

Of course the real Sherlock would have seen through Hooper’s disguise in a second, but in his mind Sherlock doesn’t because it reflects his changing perceptions of her in real life. John, on the other hand, sees the value in people right from the start, and he cared for Molly’s feelings in real life from the moment he met her. Sherlock knows this, and that is why John recognises her in the mind palace before he does.