I think Tsonga's game matches better against Djokovic. But Roger is playing worse than Djokovic so he might have a better chance against Roger if he reaches the quarters.
If we were talking about both in their primes, I'd agree. But Federer has noticeably lost a step in his defense (diminished reflexes for poorer return of serve and loss of footspeed) since his prime and has become very vulnerable to big hitting opponents, the same opponents he usually handled in his prime quite well.
Djokovic, on the other hand, is the best defender in the game, especially on hardcourts. Bar on very fast surfaces (that don't exist anymore), I believe every big hitter would prefer to take on Federer than Djokovic these days. It's not a coincidence someone like Berdych does so well vs Fed and struggles against Nole: Novak can defend him into oblivion, Federer can't. These days, even if the rest of their game isn't really 'on', serving well is pretty much enough for the likes of Tsonga/Berdych/Delpo to give Federer a really tough time and force him into tiebreaks.