Why does it matter so much to atheists that God doesn't exist?

These are man made rules - made thousands of years ago for the use of the humans who lived thousands of years ago.

I do not personally care if you believe in a god or not.

Because these are not any gods rules we are talking about.

Something Mysterious Is Hidden Deep Beneath the Pacific Ocean, and Scientists Can’t Explain It - The Daily Galaxy

I am speaking to the US Bible thumpers here, of course ~ many of whom are flat-earthers who deny evolution and see scientists as evil people who are constantly trying, and succeeding, in disproving their beliefs one by one.

The people of the modern world have evolved past all of that nonsense.

THE BIBLE IS THE PROBLEM!

What great song was "ruined" once you really listened to the lyrics?

And then use and ENJOY these fantastic scientific advancements every single day of your life?

And how do you deny hundreds of years of advancement in all fields of science?

A belief in a god is not the problem.

MAHA kids’ health report misinforms about tonsillectomies and ear tubes - statnews.com

Those rules that you are trying to reinstate are rules made by men who didn't know anything about the earth, nor anything about all of the other inhabitants of it. How can you not see that?

IT does not matter, mainly because it does not exist.

Notice that I said their rules, not any gods rules.

What made you stop being an addict?

My problem is that people who try to shove their rules down everyone's throats - including by physical force - DO EXIST .