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

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

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?

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

Autism and ADHD have distinct brain connectivity signatures, study finds - Medical Xpress

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

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

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

Most people obey arbitrary rules even when it's not in their interest to do so, experiments show - Phys.org

A belief in a god is not the problem.

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.

What thing happened to you as a child that you haven’t let go of to this day?

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 .

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.

Why am I so unproductive when it's a holiday the next day?

THE BIBLE IS THE PROBLEM!