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

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.

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

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

How long does it typically take for whey protein to have an effect on bodybuilding, weight loss, or weight gain?

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

THE BIBLE IS THE PROBLEM!

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

How does a man look at you when he is in love?

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

A belief in a god is not the problem.

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

NASA Mars Orbiter Captures Volcano Peeking Above Morning Cloud Tops - NASA (.gov)

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?

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

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

Queens of the Stone Age Announce Autumn 2025 Tour of North America - Pitchfork

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