I was being a little bit overwrought or silly here so take with as much salt as you please. But the core of Judaism is not ‘I believe in God who has features x y and z’. Rather it is ‘I am committed to living an ethical life’. Whereas you see in almost every Christian church a ‘statement of belief’ that has clear theological assertions which must be accepted to be in communion with that church. e.g. (making these up) ‘God is triune in the Father Son and Ghost, but also unitary’, ‘Jesus’ ring fingers was longer than his middle fingers’. Which is to say, in order to be Christian one must believe certain things and in order to be Jewish one must act in a certain way.