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

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

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

THE BIBLE IS THE PROBLEM!

What are some photos of female sexual organs?

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

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.

The administration’s anti-consensus Mars plan will fail - SpaceNews

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

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.

Would the word literate carry the same meaning with public (common wealth) in 1900 vs today 2020?

A belief in a god is not the problem.

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?

How did Neo defeat the architect at the end of The Matrix: Reloaded? Was it solely due to his belief in himself or were there other factors at play?

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