If you act according to a belief that "nature wanted it" then yes, you are acting irrationally. But I'm not sure who's arguing that in this thread.

The thing is, nature does know best in many ways. If we anthropomorphize nature, we are being foolish.

But if we try to understand ecology and evolution, we begin to see that nature is made up of communities. Some plants fix nitrogen and other nutrients in the soil, animals and fungi help decomposition (thus nourishing the soil), predators and prey interact in complex ways, animals spread seed and pollinate plants.

When one species is stressed, that plays out in the whole community, in ways we are only just beginning to understand. The more stressed populations, the more humans begin to take notice: forest fires, blights in valuable crop species, erosion, flooding, nuisance species spreading, etc.

Human civilization started around 12,000 years ago. We have had a relatively stable ecosystem in that entire time, and this has supported our rise. There is every indication that the scale of changes we are seeing now will be catastrophic.

So yes, in a way, nature does 'know best.'