No, I don't think he was gloating, or at least, not very much but Harman asked a very important question and dave could have answered it, plainly and without the sarcasm. He already has the Labour Party with him on the EU vote, as neither they nor he wants to comes out. I bit more class would indeed have been useful.
I found the arrogant, bullying tone unpleasant in the extreme. I suppose that Ms Harman is 'up for it' and not upset (she would give it out herself I daresay). Why can't they just debate? You know... ask questions, get answers. It's a mockery and I feel ashamed of the whole procedure these days, T.B.H..