I am saying that earth's average temperature has raised by 23° C before with zero human impact, and it will raise by as much as 23° C again, even if you cut all human carbon emissions to zero overnight (itself an effective impossibility for other reasons).

The average global temperature raising by even 2°C has catastrophic and devastating impacts to humanity, to say nothing of it raising by 20°.

We can't stop or prevent global average temperatures from rising, even if we do cut emissions to zero.

What we can prevent is the widespread loss of life (human, plants, and animals) and prosperity. Preventing loss of life and prosperity is good, and it's an achievable goal, so we should pursue that goal.