It's not thinking critically about the issues in play or how they would affect the lives of millions or billions of people, let alone the animals, plants, and microorganisms involved. It's not heresy, it's just hubris.
Do you know that in France many industrial projects are stopped because of such reasoning? For instance, a guy has a factory there, and it's working well, and he wants to expand to the neibouring wasteland, which is conveniently placed. Then some guys come and say that some specie of triton is living there and might be disturbed, and the project is cancelled, and the factory guy must build another factory far away, and it's an headache, and he gets some "compensation" from the local administration, which is just people's tax money. All of this because maybe, just maybe, a triton will be disturbed, which will break the natural cycle, which will create an invasion of cricket, which will kill us all, but just maybe... (All of this come from a stupid misunderstanding of the butterfly effect)
Also, can't we think a bit out of the party line there? I am a nature lover as much as anyone, but I think we currently do not trust its resilience enough, and it is dangerous. Am I allowed to share these thoughts? Am I rude or something? Could there still be some topics that we cannot question? Then why? Maybe these topics are weak too, and will break if we question them. Which means they will break anyway, and will break much harder if we protect them from criticism. That's dangerous.