"Steve, how come you're just not funny anymore?"
Johnson has wisecracked his way through his coaching career, along the way furnishing himself with a rugby cv that looks far more impressive than the results he has achieved, but his levity on Saturday evening was startlingly inappropriate. There was nothing remotely funny about this match, this performance or this result. The job of a coach is to get the best from his players, and Johnson is patently failing to do that.
"Well, at least you'll get some entertainment," a Welsh colleague told me when Johnson was appointed just over a year ago. I can only assume the fellow spends his days channel-hopping between Dave and UK Gold, because you need to be pretty tolerant of repeats to find the Australian funny these days. Last week, when Johnson joked about dropping Kelly Brown, it was a moment of jaw-dropping crassness and insensitivity.
Johnson has set himself up as some sort of rugby Rasputin, a bearer of the mystic secrets of the game. He talks as if he is privy to some tier of information that is only available to the sport's illuminati. To make the act convincing, he patronises his players, treat them like juveniles, deny their autonomy and their ability to make decisions on their own. It is complete hokum, but it has served him - and him alone - very well so far.
He was at it again on Saturday, talking of his players as "kids" and blaming this defeat on their youth, their inexperience and their naivety. It was the sort of mumbo-jumbo you would hesitate to use about a team of 12-year-olds, but it was also utterly at odds with the facts. Scotland went into the game with an average of 23 caps per man, while England's average was 20. Their average age was older, too, almost 26 against 24-and-a-half. In short, Johnson's arguments were specious nonsense.
And none so risible as his claim that he could have taken "the easy option" by putting out a side that would have won the game, rather than one that he is developing for the future. Maybe this failing comedian has just acquired a taste for hollow laughter, but it was an argument that plumbed depths of contempt.
Or maybe, after all these years doing a passable impersonation of Sir Les Patterson, Dame Edna Everage's uncouth compatriot, he has decided to put together a Matt Williams tribute act instead.
For, in truth, Johnson is dishing up the same old hooey about building for the future that his compatriot used to spout. The mind went back to 2005, and the litany of self-exculpatory eyewash that Williams delivered then. It was nonsense in the noughties and it is nonsense now. Frankly, it is becoming difficult to identify a difference between the two coaches more significant than the fact that the irredeemably unctuous Williams had a rather more disciplined personal grooming regime.
Of course, the 2005 Six Nations was interesting for other reasons, too. It ended with something close to dressing-room revolt when, in the final game against England at Twickenham, and as they contemplated their third 40-point defeat of a championship that had dynamited the Lions aspirations of many of them, the Scotland players tore up the Williams script and began to play with heart and devil and passion. They still lost, 43-22, but in that show of defiance they regained their own pride and the respect of their followers.
The booing that greeted the final whistle at Murrayfield on Saturday was sign enough that the time has come for some of that spirit again. Certainly, there was a sense of mystification around the Edinburgh ground following a performance in which Scotland had been pasted more comprehensively in the possession and territory battles than they ever were on the scoreboard, in which Johnson demonstrated his coaching genius by taking off his best player -Dave Denton - with almost half-an-hour left to play, and in which the Scottish lineout suffered a collapse that might have been termed unprecedented but for the fact that such things have become all too familiar.
There was some meagre consolation in the fact that the Scots showed the defensive resolve to battle to the finish. Given the chance - as he should be - Chris Fusaro will play better and more cool-headed games than this for Scotland, but he will never tackle as tirelessly or fearlessly, or leave himself so drained at the end. England would be justified in blaming the pitch for keeping the scoreline down, but some credit must given to Scotland for an effort that, from very early in the game, mostly looked like a damage-limitation exercise.
Changes? There are cases to be made. Ross Ford suffered the embarrassment of being hooked after 42 minutes, but to leave the hooker on would only have deepened his ignominy, so wretched was the Scotland performance in the lineout. Scott Lawson looked lively in his place.
At least one of the locks should be worried, too, for there was a troubling lack of energy and bounce in that area. Greig Laidlaw must also be vulnerable to a challenge from Chris Cusiter at scrum-half, all the more so as his goal-kicking has been so poor just lately. Al Strokosch appears to have drifted off the scene this year, but how Scotland could have used some of his menace on Saturday.
But England plough on. Stuart Lancaster, their estimable coach, has screwed together a front five of stalwart, yeoman virtues, has a couple of blasters in the second row and an immense talent in the shape of Billy Vunipola at No.8. In the Murrayfield slurry, his strike runners behind the scrum also showed a cutting edge in conditions that might have been expected to blunt them. They, at least, will have gone home laughing.