> With so much bulk interception going on, what's the downside?
There is no downside. Just pointing out that HTTPS is not yet as ubiquitous as you would expect it to be.
Plus, from the information provided in the article, the nature of the data that could be intercepted over Ebay or over The Register is not radically different: no financial data, but both could be used to build a profile of the person(s) behind the account. In Ebay's case I believe this included some personal data (e.g., name), while in The Register's it included account login details (making it trivial to profile a user).
That is why I think it's fair on The Register's side not to give in to gratuitous sensationalism and knock Ebay down too much about it.
Mind, there is also the issue of HTTPS not being nearly as efficient a security measure as it used to be ten years ago, but that's another subject.