atomant - Yes, to make a letter such as this "L" does take intelligence and I know this due to my experience throughout life. And a code based on those letter is likewise a sign of intelligence for those same reasons.
However, DNA does not contain letters or a code or anything like that at all. It only contain chemical compounds. That we observers give analogous definitions to those compounds for ease of understanding does not mean that those analogous definitions define DNA absolutely ...
Beware of heading into logical fallacy territory with those type of arguments atomant.