Why shouldn’t God as a hypothesis be the starting position? “Because I say so” seems to be the best atheists can come up with.
There is actually a very good answer to this question SBF. The reason we don't assume claims are true until proven false is because it would put us in the position of believing contradictory things simultaneously. If the JWs say there is only one God and the Hindus say there are multiple Gods - we're now put into a impossible situation of trying to believe two incompatible things at the same time. That's why positive claims require positive evidence.
And can you imagine a world where claims are assumed to be true until proven false? I'd be able to say, "SBF murdered kids" and we'd have to lock you up in prison until you were able to prove you had never murdered a child in your entire life (an impossible task).
THAT's why the God hypothesis - just like any other hypothesis - shouldn't be the default position. The default position is "I don't know". And then we can take a look at the world and see that every single thing ever investigated has had a naturalistic cause - and zero things have had a supernatural cause. And, as all the evidence is operating in one direction, our position moves from "I don't know if there's a God" to "There's an infinitely higher likelihood that gods don't exist than do exist."