I think there are two main avenues of possible contention that could arise if wolves ever found themselves in a populated area in the United States. 1. The dissapearance of peoples dogs. Dogs mean a lot to people these days, and it would do no favors for the wolves' reputation, as dogs noisy barkings, and estrus are two things that would bring wolves in. 2. People seeing the pretty wolves and feeding them. as has been the case in Yellowstone, people feeding them causes them to become unafraid of people, losing their desire to hunt, and ultimately creates a welfare- state wolf that seeks people out, hoping they will provide food. This can lead to an entire new set of issues that also, do not lend to a positive reputation for the lupine species.
Discussing fault i think is not productive at this point. What happens in nature every time- is an equilibrium is achieved after much loss and suffering. We have taken much of the wolves' native land (And other animals, etc) so they have lost much of what they used to have. As they return, they will no doubt seek to expand their terroitories, as they will undoubtedly find the prey abundant in their former absence. As you may well know, the presence of prey equals the presence of pups. SO if there is a lot of food, there will be a lot of wolves- they do not need to be told this, they do it on their own, naturally.
So after reintroduction, we will eventually see their numbers increase to the point where we will one day have to deal with it- which means the destruction of packs, and the destruction of lupine life. This saddens me a great deal. There are non lethal ways of controlling pack boundaries, but having dealt with these magnificent creatures firsthand I can tell you oftentimes they are more cunning than the most intelligently designed trap.
I can tell you that the chances of a wolf seeing a city for the first time, going to said city, then seeking out, or even accidentally coming across a human, deciding to eat the human, and then killing the human are less than zero. Only from feeding them will they gain the confidence they need to become a true nuisance and danger.
Can you see a 200LB wolf saying: "Hey.. HEY! You! Yeah, you! Aren't you gonna feed me? The last guy did... I'm tired, hungry, and I don't feel like running a deer down, now put some food in my snout!"
I can tell you it is a scary thing to be in a pen with a wolf and the wolf wants what you have. I made the mistake once years ago of bringing treats into the pens of 3 of the larger male wolves. They instantly surrounded me and took the food from me so fast I was like "I'm gonna get grubbed!" and then it was all over and I had no food left in my hands. The owner said "That was scary, huh." I was shaking... "No... I'm cool..."
When a wolf has no fear of man, they will take what they want from man- can you imagine someone who is not a devout wolf lover like myself being accosted at a McDonalds because someone who had good intentions decided to give his large fries to the big, hungry doggie?