Personally, I disagree. I think that attributing various "cultural" aspects of demihuman (anyone else remember that term?) races to divine will makes for a lot of sense in the context of the game world. Moradin is the one who created dwarves, so naturally he did so in a way that he found pleasing. Hence, they speak his language, are good with axes, skilled at crafting, etc.
In that context, "made in God's own image" is a very real thing in the setting, rather than a matter of belief.
Now, that doesn't work for settings where you don't have active deities (e.g. Eberron), but insofar as a default goes (which is what the Core Rules have to present) it works fine, even (or especially) if it's not explicitly stated.