DNA codes for a lot more than just genes... you're just conflating several unrelated concepts. For example, regulatory regions don't care about codons at all.

DNA codes for a lot more than just genes... you're just conflating several unrelated concepts. For example, regulatory regions don't care about codons at all. If you're just saying "genes are defined in units of codons", no complaint. And the biophysics of synonymous codons are highly complex; in most cases, you can substitute them in and get the same exact protein function. There are lots of papers about corner cases in specific proteins, but it's still correct to say that synonymous codons code redundantly (this is a well-established fact of molecular biology).