It would be arrogant for us to say humans are bad for the earth while humans are nowhere near having the technology to harm the planet itself.
To set the record, the endless oceans around us make up only 0.06% of the earthís mass. How important humans are for the Earth?
What humans are bad for is the ecosystem they and all other living things, have evolved in. In other words, fighting climate change is nothing but an attempt to save humanity from extinction due to sudden climate change.
It is true, many climate changes happened in the history of the earth and perhaps many others will happen, living things adapted to the changes thanks to evolution. However, in case an external factor accelerates the change, most living things will not have the time to adapt to the new climate in their habitat and perish.
For example, what wiped out 75% of all species 66 million years ago was stimulated change in climate, not the asteroid collision itself. What will cause a mass extinction with the next supervolcano irruption, is accelerated climate change, not the irruption itself.
If humans fail to slow down the current climate change, humans will go extinct taking countless animal and plant species along with themselves, however, new species will appear adapted to the new ecosystem. Current attempts to slow down climate change are in effect for saving humanity not really life on earth.