"To be on the offensive" means "attacking something" or "being aggressive towards something", not that the person who is "on the offensive" offends somebody in the sense that that somebody's feelings are hurt - http://www.thefreedictionary.com/go+on+the+offensive .
It's arguable whether or not a PM should be that aggressive, but I'd say his expression made sense.
Yes that's right, because the person I was replying to used "to be on the offensive" I didn't go back and check, but yes the OP used "offensive" which is quite different. My bad.
It's arguable whether or not a PM should be that aggressive, but I'd say his expression made sense.