Although arguably implied, there is nothing in this blog post that explicitly states that MIT is alone amongst institutions of higher learning in accepting a student without a HS diploma. Rather, it is simply demonstrating a particular example of just such an unusual occasion.

I'm not sure why everyone is reading into it so much: it's just a "feel good" piece, really, illustrating how one student's practical skill set -- here, coding -- was sufficiently talented to warrant a second look by one of the country's (best) universities. And, being a private school, they were willing (and able) to peel back their own red tape and allow admission notwithstanding his otherwise disqualifying credentials.

The point of the story is simply: here's a kid who was unqualified in the traditional, technical sense. But due to his obvious skill and intelligence in a particular field, a private school was willing to look past his technical disqualifications and, by its own prerogative, make an exception to its own rules.

This is most certainly why Berkeley and other public schools were unwilling to make an exception: they have less flexibility. (As someone who attended UCLA, I can attest personally to the stringent red tape of California's public university system.) That the blog throws public and private schools into the discussion demonstrates a remarkably cavalier oversight that misses the point entirely with respect to why, precisely, MIT -- a private school -- is the school that happened to grant the student the exception.