Because its true -

So.The scene. The missing scene. The scene that needed to be seen. OrHow Sherlock Holmes explained to Molly Hooper that his actions had been the result of threats, lies and pathological terrorism.How he wasn’t tormenting her for his own amusement or an experiment in human suffering. How he knows she’s a reasonable, sensible, forgiving woman. She would understand that words ripped from a victim of violent threats and astonishing cruelty were invalid, void, redundant.But Sherlock Holmes is deeply troubled, since he is perched rather horrifically upon the horns of another dilemma. He cannot tell Molly Hooper that his words were redundant, since he now wants nothing more than for her to know of the love he has kept hidden for so very long.His problem, you see, is not the explanation of his sister’s conduct, but rather the explanation of his own.OR: my attempt to explain how she forgave him.