Of course this shouldn't be sanctionized, players are allowed to celebrate in whatever manner they want, as long as they keep it, hmmm, "decent", if you know what I mean nutch nutch etcetera.
That doesn't mean every tennis fan will or even should approve of this kind of behaviour.
Personally I find this monkey-shirt ripping of Djoko's extremely repulsive, especially when it happens in a 4rth round match against an underdog player who's been playing great but just fell short eventually. A little more modest reaction would have suited Djoko a lot better at this occasion, imho.
Djokovic... some five years ago I actually appreciated him. Two years ago, I noticed I had become "indifferent" to him. Nowadays, I root for whoever is playing him. I'm afraid this celebration routine of his has played an important part in that development.