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

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

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

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

What CIA front organizations operated in the United States during the 1960s?

THE BIBLE IS THE PROBLEM!

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

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?

My dog is 2 weeks old. He's not eating, moving and always sleeping and I can't take him to a vet. What should I do?

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 .

A belief in a god is not the problem.

Has your wife or girlfriend ever been felt up in public by a stranger?

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

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

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.

How do you confront your own family for not inviting you or leaving you out of things?

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