I think the broader point that pressure is bad for QBs is true. But, maybe I'm remembering this wrong, but wasn't the secret to DAs success against Brady that he would not bring a bunch of pressure and instead played coverage?
I do think there are some QBs, especially the great QBs, that welcome blitzing to create pressure because it allowed them to get big plays. Brees was particularly good at it and so was Brady. But, obviously if you can get pressure with your front 4 and then play coverage behind them, it's the best of both worlds because you still have 7 guys in coverage to stop the big plays that you can get when there are holes created by brining additional pass rushers.
In the end, I think you can be a good QB and still have issues against pressure. But, the great QBs are the ones that can deal with pressure and make the defense pay.