It was many years ago, so sorry, I don't exactly remember.
BTW, this is not new. There is a well known bias in many Bay Area investors when it comes to founders above a certain age - where the exact age depends on the investor.
Ive seen it as a combo of too things. Confidence of ignorance and there is nothing more motivating to succeed than feeling low social status and feeling like you should be higher.
I was there too and remember something along those lines. Maybe not as absolute though. Maybe it was more "I'd invest in young entrepreneurs when no one else would"