If Djoker was the same age as Federer all these years the latter might have more than 20. Have you seen Djokovic at ages 29-31 compared to Roger? Nadal won 9 before Djoker became great too, should we discount those? Just be happy there's no real drug policy in this sport and those who get "caught" usually get set free.
This is the most ignorant of posts, and it drives me nuts that guys actually use it.
Since what you're implying is very obvious let's call things for what they are:
Why do you think Nadal is a PED user, but not Federer? It's utterly hilarious to me this line of thinking that you and Front constantly push: "Oh yeah, everyone in tennis is on drugs, but the drug policy is a joke...except for Federer of course, he's clean. You know, the most successful player of all time who's still winning majors at 36 years of age... he's clean."
To be clear, I am NOT implying Federer is on something. But if you think Nadal or Djoker are, surely old man Fed moving like a cat and dominating people should raise eyebrows?