Considering Aaron's legacy of "full-time, uncompromising, reckless and delightful shit-disturb[ing]" as so eloquently put by Cory Doctorow, he probably wouldn't have wanted us to deal with the trivialities of copyright law at the expense of a good cause.
Aaron knew about copyright's implications - hell right around the time of RSS, he helped launch Creative Commons. And he didn't put a license on his site. So maybe by not stating a license he was making a statement about copyright. But now we'll never be able to know for sure.