Can I suggest that you take a look at the goals again? definite goalkeeping mistake for the first goal, that is goalkeepers ball all day long and lest we forget they had a perfectly good goal disallowed when he dropped a simple cross.
The 2nd goal we had at one stage 3 so called midfielders following the ball instead of doing their jobs of marking unmarked players and one of those players scored, absolutely nothing to do with defenders it was another midfield failing and for the 3rd goal bearing in mind we were only 1 goal behind with 20 minutes to go, our complete midfield unit (actually an insult to midfield units) were caught out ahead of the ball, leaving 2 defenders against 3 breaking attackers, something that has been happening to us for 3 seasons.
To blame the defence is overlooking the true problem, I can recall at least 5 last ditch tackles/blocks by defenders that could have made the scoreline even more embarrassing, including one terrific block late on by Kalas.
The truth is Johnson set up not to lose with a powder puff midfield against possibly the most physical side in the championship and they mullered us all game and easily deserved to win, ergo his fault.