Good to see you, and to hear about the JW encounter. I had a similar such encounter at the door about 2008 with JWs I didn’t recognise. I predicted to them that JWs would one day accept gay people (not sure how that topic came up) but that hasn’t panned out, so far at least.
I can’t say I’m terribly impressed with the “atheists just believe in one less God” argument. Because it seems to me that the question of whether their is a God at all is a different kind of question from whether any particular tradition about God is correct.
To make an analogy, say there is a flower out of sight in the garden and there is a dispute about what colour it is. Some people think it’s blue, or red, or yellow, or whatever. Then somebody says they think the flower doesn’t have a colour at all. It is without colour. The others are confused and say it doesn’t make sense, or at least requires some sort of explanation. But the person advocating the flower with no colour insists it makes perfect sense. In fact, he says, the no-colour flower should be the default position until there is more evidence bearing on the situation. Everyone else, he points out, disbelieves in all the other colours the flower could be, except the one colour they believe in. He just goes one colour further!
Maybe it is possible for a flower to exist without colour. But at the very least it requires some explanation, and it’s clearly a different kind of claim than the dispute among others over what colour the flower is. The step between arguing that the flower is one colour rather than another, and the claim that the flower has no colour, clearly represents different sorts of disputes, and is not properly elided as being on the same spectrum of possibilities.
Saying that the universe could exist without a ground of being, or unmoved mover, or God, is in a different category from the claim that a particular historical tradition about God is true or false. Someone who maintains that the universe can exist without any God at all is saying something far more profound about the world and its instrinsic nature than that he simply fails to believe in one extra historical traditional about God. In that sense the “atheists believe in one less God” argument actually sells atheism short, because it understates the significance and depth of the issues involved in subscribing to either a world with or without God.