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?

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

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

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

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?

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

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

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

What is one fantasy you have never told anyone about but really want to do?

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

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.

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

I am a copy and paste developer, how do I become a real software developer?

THE BIBLE IS THE PROBLEM!