(Sorry, I meant to add an explanatory sentence and got distracted. One moment please.)
It's because this is a classic rage tangent, and those invariably reproduce the same result.
People exhume this quote at every opportunity as if it adds light to the topic at hand. But this is an optical illusion: it only appears to do so because it's the most cherry-picked detail ever. All it really adds to the discussion is a rage supplement, like one of those toxic fuel additives.
If you picked a bad thing I—or any of us—said, and brought it out at every apparently relevant moment, you could make me—or any of us—look just as bad. The only differences are that the horrible things I said at 19 have been forgotten (at least I hope they have) and I didn't turn into the CEO of Facebook or some other celebrity.
These single-purpose memes are a side-effect of how the Internet works (https://news.ycombinator.com/item?id=9722096). They're reflexive, not reflective, so they don't belong in HN discussions.