Thing is, nobody would have "reasonably" expected the results across decades of the "management" of Yellowstone, including the scientifically approved ideas of eliminating the wolf population or preventing normal seasonal burns, both of which produced horribly damaging unintended consequences.
Which were then realized and corrected, and did not end up with catastrophic failure of Yellowstone to continue to exist as a thriving ecosystem. In what scenario do people start to wipe themselves out with their attempts at curbing climate change and decide, hey, whatever,
we absolutely, positively, refuse to change course?
Who would have "reasonably" expected massive oil spills in Prince William Sound or the Gulf of Mexico?
Oil spills are not outside the realm of reasonable possibility.
And of course, when the War on Drugs was the in thing, nobody would have "reasonably" expected that the inner cities would become war zones or we'd become the most incarcerated country on the planet.
Violence in this country has actually been going down, not up - and are we really sure the war on drugs is directly responsible for the rate of violence? As to the incarceration rates, that's not all due to the war on drugs either, and the part that IS because of the stupid war on drugs has gotten enough attention that measures have been passed across the country to mitigate that problem. Again - it might be slower than we'd like, but we are perfectly capable of changing course if something has the potential to go catastrophic. If we weren't, the entire "should we drastically change course in order to prevent ecological disaster" discussion would be moot. And in these cases, catastrophic does not mean "no more advanced civilization for mankind."
I'm not going to keep going point by point; I'll suffice it to say that there is a wide, WIDE gulf between policies that had negative unintended consequences that were well within the realm of possibility, and that were affecting things considerably smaller the world's ability to support human civilization, and were, for the most part, things that we could back out of and change course, and OMG teh world can't function anymore due to ?????