I don't get your logic. Nadal's only problem right now is Djokovic. Rafa simply owns Fed... why would it hurt more to lose to Fed lol?
How would you feel when you lose to the same player 7 times in a row? not fun.
Because Federer is the GOAT. The player all others will be measured by in history, until Nadal replaces him. In 10 years, nobody will care what Nadal's h2h is vs Djok (btw it's still 16-14 Nadal, and 5-3 at slams). Nadal vs Federer rivalry, will be talked about forever. So the bigger lead Nadal can get over Federer, the more glory historically for Nadal. Every Fedal meeting is historical gold for Nadal.
How would I feel if I lost to a player 7 times in a row? The same way Djokovic felt when he lost to Nadal 5 times in a row. 5, 7, it makes no difference.