> the Audubon Society and the Cornell Lab of Ornithology oppose [trap, neuter, release], holding that cats are a highly destructive invasive species that should not be allowed to live outdoors at all
The only option that leaves, really, is extermination.
But nobody is going to do that (not on a scale to have an impact, anyway) because (1) it costs money and (2) people would flip out because they love cats.
Is the the Audubon Society society going to step up to pay the bill and take the blame? Will local government agencies? I don't see it happening.
Meanwhile, TNR runs on very lean budgets because it's all cat-loving volunteers.
Of course, I'm not sure it's actually effective. But, so far, no one is proposing an alternative that could actually be tried. The Audubon Society's position is effectively identical to ignoring the issue entirely.