"It wouldn't have been the same result, as in the scoreboard," Johnson said flatly. "I thought we were in the contest, but full-back is a hell of a position to fill for that length of time.
"If it's a forward you can cover it, but it's harder to cover a back division player, and once Wales were on a roll they played some pretty good rugby, too. There was a lot of ground to cover and it was difficult for us."
Johnson refused to criticise French referee Jerome Garces for changing his yellow card punishment to red after reviewing video footage of Hogg's shoulder charge on Wales fly-half Dan Biggar.
"I work on the theory that referees are paid to do their job," he said. "As soon as I saw the yellow I was thinking of something else. The judicial stuff I'll leave; my job is to compete on the back of that. He's a good referee and a good adjudicator.
"Stuart is really down about it. He's taking it tough. He's an emotional lad and that emotion is a good thing, but in this case he is feeling he has let the boys down. He has to face the reality that he has been caught doing something. He has a proper tribunal to front up and show his case. So he's in a dark place, but that's just life. He's got to confront it.
"It was totally out of character. He might be many things, and one of them is a great character. He certainly isn't a dirty player - that's for sure. He's already been in to apologise to Dan Biggar and the referee. It's so totally out of character for him."
Greig Laidlaw, who took over the captaincy after Kelly Brown was taken off with a head knock, agreed the challenge had become far greater for the Scots after they were reduced to 14 men. "We certainly knew it was going to be a lot harder," said Laidlaw, who added that he had never felt under as much pressure as when defending against Wales. "Coming down here is hard enough. But credit to Wales because they played pretty good rugby and made us pay, but there were a lot of errors in there as well which compounded which was already a poor situation."
However, Hogg gained unlikely support from Wales coach Warren Gatland, who was the player's coach on last year's Lions tour to Australia.
Gatland said: "You've got to feel sorry for Stuart because he's not that sort of player at all. It's a rush of blood and he's made a mistake. From our point of view, we are not going to dwell on it. I don't think you'll see that from him again. It's a collision sport; from our point of view, there are no hard feelings."
With Johnson now moving to a new role as director of rugby and Vern Cotter coming in as head coach, Laidlaw paid tribute to the man who has held the reins since he took over as caretaker from Andy Robinson 15 months ago. Laidlaw said: "I think the players definitely like Scott and he's definitely brought a different edge to us in terms of the way we train and the way we have been playing in some of the performances we've put in while he has been in charge.
"As a group of players we are extremely disappointed to let him go on this one. He's been good to us and he deserved a lot better, so we're absolutely gutted with the way today has turned out."