Why atheism always has a burden of proof

[Bad Writer]

I don't believe in a god because I haven't found sufficient evidence to do so.

Call that whatever you want to. I just don't believe in the unproven idea of the god concept.

What constitutes sufficient evidence?

You looking for God in a test tube or something?

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So do you believe in mermaids? Yes or no answer please.

I don't believe mermaids actually exist, other than as fictional characters.

Let's start with whatever evidence convinced you that there is a god. That's the evidence that will be examined by those you are trying to convince.