Again: people do a lot of dumb stuff when they're 19.

I'm assuming you've never met Mark Zuckerberg. All you have to go on are his portrayals in the media.

Have you ever said anything racist? Sexist? Discriminatory, widely insulting? Have you ever joked about things you would do to take advantage of other people?

How would you feel if any one of those things were held against you by everyone years later? I've personally said worse things, and I've later regretted them. I'd be mortifed to have them follow me for a decade. The man is turning 30 soon. It was literally a decade ago. Let it go.