"Limiting the profession to those who started naturally at a young age is a good way to keep out everyone but rich mostly-white kids with college-educated parents."

I would say it weeds out everyone who was not inclined to study programming or was not in a situation that prompted them to start programming.

Frankly, this is a childish presupposition. Let's imagine if surgeons where expected to have begun surgery for fun at the age of seven.

It's a cop-out excuse from teaching establishments (if used) and it's a harsh and exclusive requirement from colleagues, more fitting of a puerile fraternity than that a professional cohort.

What one does need, is a certain fluidity in language skills, logic, and most of all, most importantly, a will to learn.

Yes, it needs a lot of work, and it's not easy, but let's not invent imaginary boundaries for peoples careers and lives.