You're right...they're not. Wolves, especially the Canadian Gray variety we have here in Idaho, are the serial killers of the animal kingdom. Just last week, two...TWO...wolves killed 167 sheep in one night in Eastern Idaho. They partially ate one sheep, and killed the rest just for the hell of it, apparently. They've wiped out the elk here in Idaho, and are working on wiping out the deer and moose. They need to be re-eradicated.
Scouts Out! Cavalry Ho!
The two wolves killed about 10 sheep and ate one. The rest, mostly lambs, were suffocated or trampled trying to escape.
Agree with you, though, about allowing large killer animals to roam our country. California banned hunting of mountain lions and now all of our parks have huge signs warning against them. Hiking alone can be really scary here even though the chances of encountering a lion are very slim.
By definition, predators don't "wipe out" prey animals.
The elk population may have been artificially increased by the absence of predators, which human hunters obviously prefer. But the ecosystem is probably healthier as a whole with prey/predator balance in place.
Michael Crichton wrote some excellent stuff about our various and varied attempts to "manage" the ecosystem of Yellowstone over the last century+. Has not been pretty.