Since a negative can’t be proved, you’re asking the impossible, then preening when it isn’t done. Fail.
They state there is no G-d. Then they say for me to prove G-d exists. Doesn’t work that way. They have to state why they’re an atheist. They can’t just come out with a statement and I have to accept it.
That's a myth. Negatives can be proven, and are, all the time.
"Some swans are not white" is a negative. Proof: Present a black swan. QED.
What cannot be proven is a universal negative: say, "No swan is red." To prove it true, you would have to have exhaustive knowledge of all swans. The best we can do is an inductive argument: based on all the available evidence, no red swan is known to exist. (But who's to say there isn't one paddling around a forgotten pond somewhere in Paraguay?)
Of course, positive atheism asserts exactly such a universal negative.