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

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

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

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

Why do people mourn when their leaders lose elections? Is it common for people to cry over events that are out of their control?

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.

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

Why do most atheists in debates with theists take Bible verses out of context much of the time? Are they lying maliciously or do they not understand theology enough to understand the meaning?

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

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.

Im not transphobic/homophobic but, am I in the wrong for being uncomfortable when a trans person comes into the lockeroom? I just dont want them to stare at me while Im changing.

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.

THE BIBLE IS THE PROBLEM!

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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?