I think, the existence of God* makes perfect sense – or at least as much sense as laws such as gravity, relativity theory, uncertainty principle do. The doubt really is about whether there is a purpose to this universe? And if so what is it; then the further doubt is about if God favours believers+ over non-believers**? Thus, God makes perfect sense, till we bring our random shopping lists of desires into the picture^.
However, there is a difference between laws of nature and God, because you see, God makes sense only when God is THE lawmaker of nature. I mean, you can have gods, who are laws of nature, but eventually there will be a God – who is the unlimited ultimate and conscious.
*God who is universal consciousness and all the matter in the universe too.
+ which does lead to the question about "who we are?" doesn't it?
**which, if I would hazard a guess, is absurd an idea as the idea that gravity favours birds but not elephants
^which is fairly confusing because all religions seem to project God as a conditional or unconditional wish fulfiller