Let’s reason together …
It is a brute fact that people are all generally moral, all generally rational, all generally common. To say there is a god because of these brute facts is to state something which is not a brute fact; it is pure metaphysical speculation. Therefore, we can doubt what is not a brute fact and doubt anything said about them that is not itself, a brute fact.
Christians, stop telling the non religious they cannot be good without God. There is nothing making you more uncommon than anyone else; no support in scripture that suggests God’s nature is imputed to yours having accepted Christ. And by way of observation, something happens to many Christians as they accept Christ. They QED the counter argument against the idea “only good with God”. It seems many make the case that being good with God is made nearly impossible having accepted Christ.
Would-be apologist, actually think, eh! The only epistemological basis for thinking there are gods is that you think there are gods and that you believe this more than you doubt it, end of story. The Christian apologetic can only be in that case, showing there’s something that matters about your beliefs, something to believe in, something of value. The answer there is one of action rather than words.