Rich people are more likely to advocate open borders.

Again, I'd be interested in the statistics. (That isn't a coded way of saying I think you're wrong, by the way. But I'd be interested to know how big the differences are, whether it depends on what you mean by "rich", etc.)

Mark Zuckerberg [...] Bryan Caplan

I'm not sure why this is relevant. I'm guessing that both of those people advocate open borders, but surely the absolute most any observation of this form could show is that there are at least two people in the world who advocate open borders for bad reasons, or advocate open borders but are terrible people, or something. How can that possibly matter?