I actually agree with what he says. Personally, I have explored such sites a bit when I first got ebooks, and found most of them not up to par. I would rather have the 'proper' version. But most people aren't as picky as I am and many people I know do not re-read books (I do). So someone like my mom who will only read it once may view a download as the same as going to the library and chalk up the odd error to those old library books you would get with the coffee spills on them from previous borrowers.
The issue is that people expect to do the same behaviours with ebooks as they do with print books. So for example if I could go to my mother's house and borrow a paper book from her, why is it wrong to share an ebook? It is the same net result. Overlooking the legal aspects and going just on a reasonable person's common sense, it is the same thing.
What they need to do is either decide they are selling a single-use rental and price it accordingly, or continue selling ebooks as a sale but bring the prices more in line with what readers are willing to pay. If I am paying full hardback price, I expect to keep my privileges. But if I only had to pay $3-4 and the book expired after 30 days, I would be fine with that.