A few lifetimes ago at SES New York in 2006 Matt did explicitly deny any ranking preference for .edu or .org sites (I do not recall what he said about .mil because I have never seen on in competitive SERPs). At the time, he said "there may be something about their linking profiles" that makes them rank better than .com sites.

That comment is what made me start experimenting with outbound links as part of a link profile. Since then, I have heard many SEOs repeat the idea that quality outbound links help you content rank. This still falls short of proof, of course, but my opinion is that Black Hole SEO is a mistake.