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

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.

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

With so much evidence supporting the flat Earth theory, why aren't more resources dedicated to studying it?

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

A belief in a god is not the problem.

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

How much stronger is an average man than an average woman?

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.

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

How would you describe modern day Russian society, beyond just politics?

THE BIBLE IS THE PROBLEM!

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.

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

South Florida-based Silver Airways shuts down, stranding travelers - Sun Sentinel

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?