I don't see how clicking a link (and downloading an mp3) is too complicated.
Explain yourself.
My usual reaction to such an abrupt demand would involve expletives, but what the hell.
The process you're describing would have to be manually managed. This would be an administrative nightmare for the SGU team, who would effectively have to handle each individual PayPal payment by sending a specialised reply. If there was a single MP3, it might work, but the assumption is there are going to be multiple MP3s released over time.
From a user's point of view, I have to make a PayPal money transfer to a designated e-mail address for each MP3, or presumably collection of MP3s, that I want to get. Since they'll be released incrementally (my assumption based on what's been said so far), I'd have to do this each time. There'd then be a delay waiting for the SGU team to process my request, and send the link to me by return e-mail. As you say, downloading it at that point is indeed trivial. Of course, then I have to manually add each such MP3 into whatever software I use to synchronise with my device (for the majority of users who do that).
While it is obviously possible to automate the back end (thus reducing the administrative overhead), it would be non-trivial to set up. Some investment would be required, and an ongoing maintenance commitment and server/support cost. The impression I get from Steve and Jay is that they want an off-the-shelf delivery and payment system that requires little time on their part. I (for one) would prefer the SGU team focussed on producing content for the podcast, rather than having spend effort or money re-inventing the e-commerce wheel.