Even worse, they don’t even have a decent definition of “God”. If they say something like that they worship “the God of Abraham” or “Yahweh” or “Jehovah”, that’s about as good as they can do to actually describe “God”, just giving it a name.

If you ignore names and just ask them to describe “God” by its attributes, and get really into details, you’ll find that no two Christians believe in the same god, and in fact, somehow, the “God” they describe will closely reflect their own beliefs more than anything else.