Why say this? This post is fine explaining the preference to get to know entrepreneurs well and the apparent mistake entrepreneurs are making by approaching investors whom don't know the entrepreneur at all. But it seems to me that Demo Day is just another opportunity to hear an angle on a product as well as getting to know the entrepreneurs behind it.

And why was he having a conversation with Christina from USV if he wants to get to know entrepreneurs better? Then, why let the entrepreneur finish? Put on the Tom Hagen face and tell him "Now, wait just a minute" and start grilling the entrepreneur with questions to get to know him better. Maybe there is something I'm missing about why as an investor you wouldn't play this to your advantage. (As for the point about learning whether the investor is an asshole, this is Y Combinator: don't be an asshole or it is unlikely you'll have the opportunity to invest again.)

The investor is usually the veteran, the entrepreneur is usually the freshman. School him. That's the duty of the veterans in the game.