What is the Most Prominent Factor in the Human’s Annihilation of Themselves and Other Sentient Beings?

I would think that the human mind is the biggest factor in the annihilation that Darwin saw humans heading toward. They have much more thought capacity than any other animal, which leads to superiority and inferiority between races and ethnicities, body types and hair, and facial features. Humans always want to improve this or improve that, advance this, make that easier. In the process though, humans have destroyed a good portion of the planet's plant and animal life. Humans have created harmful chemicals, genetically modified animals and plants, and polluted the earth in the process.