Sure, chemical reactions are spontaneous, but we're talking about DNA coding, where a string of chemicals translates into physical features in a living creature -- not salt, not just some other chemical product, but traits in a LIVING CREATURE. That's rather a different order of "code" wouldn't you agree?
How is it different?
Why can't we describe all chemical reactions as being guided by a code?
But that's exactly what this semiosis seems to be - a meaning inherit in the sequence of bases on the DNA molecule - inherently able to couple with the protein-building system, which is inherently able to produce proteins in the right amount, at the right time, and deliver them to the right place to make life possible.
That's only because the sequences that resulted in life dying were eliminated from the gene pool.
The combinations of chemicals that did not result in reproduction were quickly swamped by combinations of chemicals that did. It is simply a feedback loop.
Added by edit: It is no different than feedback through a microphone and speaker system. White noise will result in a single tone being amplified above all the other frequencies because that one frequency happens to be "just the right one".