I think most if not all of the negatives are fiction. The lack of understanding is holding back a genuine fix to our biodiversity problems.
While I think the idea of reintroducing wolves back into their native habitats is an exciting idea, I feel it's very important to not undervalue and wave off the concerns some people have. One of the things a lot of people don't realize is that wildlife is in our world just as much as we're in theirs and sometimes it causes genuine friction. There's the general nuisances you get from time to time, like rabbits in your vegetable garden, raccoons in your trash, or mice coming into your house in the winter, but there are also more serious situations as well. Cougars have been known to joggers and children playing in the park, coyotes go after livestock and domesticated pets, moose get terribly aggressive during mating season, and on and on. Some things, like shark attacks, are overblown, but the risks we take when we live among wildlife is very real. It's important, in conversations like this, to acknowledge that so we can open up a dialog with people to help address their concerns and come up with solutions. Otherwise, you'll have situations where people constantly freak out about shark attacks when they're one of the more rare animal encounters that occur.