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

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

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

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

My scammer is blackmailing me. If I don't pay 300 euros, he will send my intimate photos to my relatives. What should I do?

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

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.

What do you think of the 2 female 18 and 19 year-old German tourists, detained in Honolulu, strip-searched, put in green jumpsuits, placed in a holding cell and the next day deported, for the terrible crime of not pre-booking a hotel for their trip?

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.

A belief in a god is not the problem.

Can cheating be a result of not truly loving or caring for someone, or is it sometimes just a spur of the moment decision?

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?

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!

How can Democrats not feel hypocritical when they urge Trump not to be vengeful should be become president when the Democrats are trying to put Trump into prison?

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