Because it was an option.
He treated it like poverty tourism, like a middle-class youth group "missions trip" to build huts for third-world natives.
Good on him for having an epiphany, but I'd wager that he'd have a different perspective if he had to do that job long past his soft-handed tendonitis episode in order to feed his family that he barely mentioned in his interview.
Imagine having built so small of a life for yourself and your family that in order to get a reality check, you have to check yourself in to rehab with the "common folk" in order to rescue yourself from your "depression".
It's lamentable, not commendable. It has all happened before, and it will happen again.
This is not a salvation story; it is a cautionary tale. He that hath ears to hear, let him hear.