That's funny for someone that doesn't even play tennis. How would you even know the difference? You do know doubles is played by a lot more people than play singles, right? Yes, that's the way tennis is.
You only think doubles is not as important as singles because Nadal has no chance ever to win a gold medal in doubles.
If Nadal wins the gold in singles and Federer wins the gold in doubles, guess what? They will BOTH be Olympic gold medalist for the rest of their lives. People will always refer to the BOTH of them as "Olympic gold medalists". When they die, their obituaries will start with "Olympic Gold Medalist Rafael Nadal" or "Olympic Gold Medalist Roger Federer".
Do you think Micheal Phelps feels any less proud that none of his 6 gold medals (soon to be 8 ) are for the 100M freestyle? Not one bit!
Anyone who wins a gold medal wins a gold medal for their country. That's all that counts. It doesn't really matter which specfic event in swimming, track, equestrian, wrestling, boxing, gymnastics, rowing, fencing, etc., or tennis that you won. The fact is you were the best in the world in the competiton and you won a gold medal in your sport.