No he performed better. Look at the full picture.
Rafael took over the club in free fall, which had been destroyed by McClaren and were all but relegated. Bruce took over a club which had consecutively finished mid-table in the Premier league for 2 seasons and had a top 8 level defence and had started to be rebuilt by Rafael. Bruce then spent mode money than Rafael, to finish in a worse position. Rafael left Newcastle in top 8 level form. Bruce has left Newcastle in 19th without a win all season.
You are putting an awful lot of interpretation in, in place of what happened intrinsically. Which is fine, and opinions are fine, but they are not facts.
Benitez took over a team that was outside of the relegation zone, when games were equalised. A team that had been mid table before that. He took them down. They sacked McLaren as he was ear the relegation zone, it was a big shock when they went down.
When he brought them up, they got the same points as Bruce and finished lower mid table both seasons. They were a lower mid table team. Bruce has kept them at lower mid table in the 2 full seasons he has been there.
Those are the key intrinsic points. You can make a number of other points and opinions as context to it, but to argue they have gone backwards under Bruce is not true. He did an equivalent job as Benitez.
Reminds me a bit of Allardyce here. On the face of it, did a good job, but he was an objectionable person who didnt know how to play the game.
Your argument that Benitez left them top 8 when they finished 18th, 12th and 10th under him is ludicrous I'm afraid. I believe they were 12th in that final season, and flirted with relegation for most of it. Trying to re-write history doesnt do anyone any good.
Either Benitez is overrated, Bruce is underrated or a bit of both.