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

A belief in a god is not the problem.

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

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

My waist finally looks like how it did before I had kids but I didn’t lose weight. Why am I still 15 lbs from my starting weight?

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

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

THE BIBLE IS THE PROBLEM!

Why do Argentinians use "vos" instead of "tú" in informal speech?

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

IT does not matter, mainly because it does not 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 Adding More Bananas to Your Diet Could Impact Your Blood Pressure - Prevention

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.

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

A cardiologist overhauled his diet to boost his longevity. Here's the grocery store path he takes to stick to his meal plan and avoid bad foods. - Business Insider

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