Okay, this is how you showcase fanworks. Not for shock value, not to embarrass the actor, but to say “Look at this awesome creative stuff your fans are doing.”
And consider that if the Fallon people looked at the letsdrawsherlock tag, they MUST have seen some Johnlocky stuff, or some porny stuff, and they didn’t use it. They only used stuff that was just of Sherlock.
Two for you, Jimmy Fallon