Only to a point. A good camping jungler will hang around for a bit, go clear a camp really quickly, head back to wait for another opportunity, go clear another camp. If they do this too long, yeah they get punished by a lack of XP and gold since they aren't getting kills or assists. But that isn't generally a problem as if a jungler is camping a lane they're either getting those kills/assists or getting their laner ahead in CS to the point where they've successfully gotten a laner minion fed, which can positively affect the remainder of the match.
No, the real balance of camping lanes is that once a jungler has clearly pitched a tent, it's
A) easier to get vision of him since you can focus your defensive wards in the areas of jungle near where he's camping and
B) you can push other lanes with relative impunity