To repeat again, he was getting owned by a teenage clay courter on hardcourts. What does that say about all the hardcourt players of the time?
Well, I think you can work this out yourself. In the year Nadal first beat Federer (2004), how many times did he reach the semi finals on hardcourts? Once. In Federer's peak years, how many times did Nadal make it past the QF of a hardcourt slam? None.
So, Nadal was beating Federer (albeit on slow surfaces), and yet was being stopped by these 'mugs'
. The conclusion is that Nadal was winning, not because he was such a great hardcourt player (otherwise he would have done much better in this 'weak era'), but because he was a bad matchup for Federer in particular.
Weak,weak,weak field of one slam wonders, 35 year old Agassi, mugs showing up in slam finals to be destroyed, teenage Rafa still learning the game etc...
Who cares? Lets all agree that Federer played mugs and wasn't tested at all.
The question is how would Fed have fared against tougher opposition? That question isn't answered by pointing out that Fed faced mugs.