They mention that boy is was one of the youngest to sail around the world by himself, at the time, as a homeschooler who did something cool to get into Harvard.
If he really did it *to* get into Harvard, then that's a failure of Harvard's selection process, I think. As I understand it, what these colleges are trying to look for is what the young person does on their own initiative, with their own drive, not because they want to impress anyone or get into a specific college, or because their parents support it, but because they themselves truly want to.
I think this, then, could work as an argument for or against homeschooling, depending on the child, the environment and the family, and of course on what the available school alternatives are. Homeschooling obviously gives more flexibility in what time gets spent on what, and also *might* give a young person more practice in making their own decisions about what to do and what to learn (unschooling having a clear advantage there!). OTOH, with a closely managing parent, the child might actually get less practice in making decisions than at school. Depending on that and other circumstances, a homeschooled child might get more or less chance to get interested in things that don't interest the parents and pursue that interest.
Either way - school or homeschool - there's obviously a balance to be struck between making sure one's child gets to know about enough different things that might turn out to be passions, and making sure the child gets enough spare time and space to try out interests and practice making choices and living with the consequences. Personally, with my DS at school, I feel that he needs almost all of the other time in the day to spend as he wants, so he does no scheduled activities outside school and the couple of afterschool clubs he chooses. If we were homeschooling, I'd probably be encouraging him to enroll in classes for this and that as the balance might be the other way.
Incidentally DS has done fantastic holiday activity weeks where he had free choice from dozens of activities, and has developed a passion for fencing, which is almost the last thing I'd have guessed he'd enjoy. I'd heartily recommend taking advantage of that kind of thing if possible: the chance to try activities out on impulse, in small doses without long-term commitment, is invaluable.
But also, don't over-estimate the importance of non-academic interests for academic success, and don't forget that world-class education is international these days and policies differ. The UK's top universities, for example, care* hardly at all about non-academic interests: admission is based almost entirely on academic criteria, assessed by examination and then by academic interview. There are better reasons for doing non-academic things than to get into university!
*as a general rule: in Oxford and Cambridge, admission is devolved to colleges and individual admissions tutors might behave differently, but I'm reporting on typical experience based on a limited but non-trivial set of information from both sides.
