It's the jump from word-as-sound to word-as-symbol, which I think a lot of people never make, partially because it's not particularly useful in their lives.
I suspect those involved in programming skew very much towards the word-as-symbol, but whether that is causative or correlative I can't say.
I definitely belong to the word-as-symbol camp when reading in my native Norwegian. Besides, I am a programmer (A shoddy one in all but assembly language, though...)
Interestingly, perhaps, is that I recently made the transition from word-as-sound to word-as-symbol in another language - morse code; that felt very odd while it was going on - I have parsed words character by character for a couple of decades, and suddenly, I found my decoding lagging further behind - I had started hearing words as units, rather than composites of characters. Funnily enough, it was through no conscious effort - just happened, over the course of a few hours.
I suspect those involved in programming skew very much towards the word-as-symbol, but whether that is causative or correlative I can't say.