[logfromblammo]

It is unclear whether that is due to lack of aptitude, lack of desire, or incorrect expectations.

The qualities of those people who have ever successfully written software programs suggest that there is no magical determinant that would prevent any motivated person from doing it.

Apply the construction from the Pixar film Ratatouille. "Anyone can cook" does not mean that everyone can, just that there's no one who couldn't.

I suppose some kinds of brain defect or brain damage could prevent it, if you really want to pick nits. But in that case the condition would likely also prevent that person from doing much of anything else.