"Ultimately responsible for the behaviour of your Cabin Crew"..absolutely, but as you are aware it is difficult for the Captain to be aware of all that goes on in the Galleys. I honestly believe the vast majority of my colleagues are professional when on board the aircraft, but there are always a few who "let the side down", I just hope it wasn't on one of "my" Flights.
Yes, we are supossed to make a Announcement following a Go Around - when/if circumstances permit. But even if it appears stable "down the back" and people are wondering why the Captain hasn't said anything, all may be completely different on the other side of the Flight Deck door; the Flight Crew may be working like the proverbial one armed looking at Fuel Remaining, Alternates available, "do we stay or do we go" (i.e; Divert) so there genuinely may not be time for a few soothing words. Having said that most of us have a suitably non-commital speech for such circumstances.