Does Duskblade discourage warding?

Playing a lot of support lately, and it's definitely discouraging when one champ with Duskblade clears all of my wards in one sweep as they haphazardly meander through the jungle.

I think the Blackout effect of hiding the champ from wards is fine, and seems to be in line with the thematic concept of the item, allowing assassins to move stealthily through the jungle. But being able to brainlessly find every ward they are within half a screen of, and destroy it with one hit, seems like too much to me. It basically turns them into a walking control ward, transfers the counter-vision to their entire team, when it seems like it ought to only hide the champ who invested the gold in the item.

I'm a low-elo player, so my game knowledge isn't exactly S-tier, but vision/counter-vision is a pretty interesting game mechanic, and seems vital to the support role. It just seems like Duskblade removes that element from the game too easily.

Am I missing something? If someone else understands why this item needs to be this way, I'd appreciate the explanation.