The problem with DNA 'source code' is not that it's hard to read, it's that we don't fully know how to read it. Yes, we know what protein sequence comes out but the chemical consequences are not particularly well known. With google's source code, you could, in theory, look at it long enough and have a working understanding down to the level of electrons moving around specific spots in the chips in the Google datacenter.

As a professional (wet) biochemist and also a coder, my personal feeling is that biology is much, much shallower. However, the knowledge required is broader but incomplete. If you're trying to, say optimize an enzyme, beyond molecular biology, you'd do well to incorporate knowledge from biochemistry (is this an active site amino acid? Maybe I shouldn't touch it. What sort of yield changes can I expect if this enzyme catalyzes the rate-determining step vs. not), cell biology (will adding this amino acid sequence send it to the wrong compartment?), biophysics (will changing this residue mess up the protein fold?), electrochemistry (is the electrical potential of this iron-sulfur cluster consistent with the process I want?) etc etc.

A lot of 'biohackers' are script kiddies that just ctrl-c/ctrl-v gene sequences and hope that it works. That's why you see a lot of gene synthesis companies claim a offer of "codon optimizing" a gene. It's something that sounds hard, sounds critical, and gets something done. The rest of it is much, much harder, and requires actual thought.