LJ Interview with Harvard's OA Architect

LJ's Academic Newswire today features an interview with Stuart Shieber, In New Job, Harvard Professor Downplays the Role of “Revolutionary”.

Highlights:
He is fostering a relationship with Harvard University Press in an effort to support the mandate. HUP is in the process of starting up an "open-access, faculty-edited journal,The Journal of Legal Analysis.
Ambiguous quote: "Authors don't get underwriting help from the library when they publish in OA journals, while they do from publishing in subscription-based journals," he explains. To put OA and subscription journals on a "level playing field," he suggests, "you'd want to underwrite OA journals just as you do subscription journals." Wouldn't a library (or journal otherwise underwritten by readers) be a subscription journal? I realize advertising, author fees, and donations are also forms of underwriting, but I found the quote confusing.