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.

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

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

How do teachers justify punishing a student for fighting back against their bullies?

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

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

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?

U.S. blasts Hamas response to Gaza ceasefire plan: ‘Totally unacceptable’ - The Washington Post

THE BIBLE IS THE PROBLEM!

A belief in a god is not the problem.

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

Wall Street warns Trump aides the GOP tax bill could jolt bond markets - The Washington Post

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

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

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

Is it possible for buyers to negotiate after an inspection if the appraisal is lower than expected?

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