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

A belief in a god is not 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.

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

Which city should one visit between Nice and Cannes? Why?

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

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

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

What is the most inappropriate thing your wife has done in front of you?

These are man made rules - made thousands of years ago for the use of the humans who lived thousands of years ago.

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

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?

What exactly is the boundary men should follow while looking at girls so they don't call them perverts?

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

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

THE BIBLE IS THE PROBLEM!

Why did Lord Shiva lust after Mohini - how can he be the supreme and worthy of devotion if he did such a thing?

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