It’s not really a question of “authority”.water said:In the name of what do atheists demand that theists present proof of God?
What gives them the right to demand such proof?
The burden of proof is on someone making the positive claim. If someone tells you that flying pink unicorns exist, it’s up to them to provide some evidence to back up their claim. There’s no need for you to disprove that flying pink unicorns exist before you decide not to believe in them.