this bit makes sense, John thought maybe, MAYBE, Sherlock was on the mend; that he was on his way to being a normal human being. But now he can see the cold hearted thought process and he sees now how Sherlock has regressed. ---> THE FEEEEEELS
In "A Scandal in Belgravia" Sherlock calls Lestrade to tell him that there's been a break-in at Baker Street. Sherlock tossed the American out the window, repeatedly. Lestrade would have had to explain it without implicating Sherlock in a crime.