I'll do your dirty work then.
Why not?
Higher average speed on the flat or downhill doesn't impact the wattage output and fatigue accumulation in any significant way, I don't think. Especially if you factor in better aerodynamics.
On the climbs, okay, sure, but I assume that in both stages, the riders will have ridden the earlier climbs at a wattage level relative to their threshold in quite a similar way.
The best indication for these things is probably the size of the field at the bottom of the final climbs. Now, I haven't been counting the number of riders on both of these two stages but the fact that Nils Politt could lead the bunch over the Tourmalet probably tells you that this wasn't the hardest stage, even if the speed was high.
There's also a problem with the absolute statement of the two factors 'cancelling each other out'. It's obvious that higher speed does increase fatigue but to say that it does so much so as to cancel the other three climbs they rode on the 2001 stage is like saying 10 minus 2 equals zero.