The reintroduction of wolves is very controversial and unreasonably emotional in the Western US. Yes wolves kill things, but they create a natural balance. For some reason, this bothers some humans who believe that balance can only be achieved through the intervention of humans.
Back in the 70s, when over fishing, logging, and mining began to decimate the salmon populations in Washington State, some fishermen (not all of them by any means) took to carrying rifles on board their boats, and would kill seals on the assumption that seals were eating too much of the salmon. I used to wonder why salmon were in such phenomenal abundance before fishermen started killing seals. It seems humans are not very good at understanding the big picture and don't really get cause and effect. Sure we see causes. We see effects. But we often don't put the right cause with the appropriate effect. As a result, we invent solutions that don't work, and often make things worse.