Regarding that People for the West mention above, I worked for them in the late 1990s and the organization folded (lack of money) in 2001 or 2002. But yes, there is the Wildlands Project, Yellowstone to Yukon and all those are directed at "rewilding" huge areas in not just western America (includes Canada). If you hear someone talking about "conservation biology" and "migration corridors" and "keystone species," that's all part of the theory.
In practical terms, there's also the idea that wildlife populations should be controlled by the top non-human predators, such as grizzlies and wolves so the ecosystem runs without human interference, that's "deep ecology."
While this worldview is not held by many, the fact is, those who DO support this stuff, really support it. If having bears means no hunters, that's okay with them. If having wolves means no ranching, or no hunting, again, okey dokey. And there's so much passion, it results in MONEY and LAWSUITS and POLITICS to the point where the resource sectors and consumptive uses are being singled out and wrecked one by one.
THink how this mauling helps the cause.....that little jolt of fear before booking the trip. The frustration over having tags and then being screwed over by some judge after booking a big money trip. What about next time, will you apply, or do something else?
That bears and other predators are dangerous to human activity, for most of the wildlands acolytes, that's a GOOD thing.

Up hills slow,
Down hills fast
Tonnage first and
Safety last.