Was there a suggestion that Project Gutenberg should not host .epubs?
What I have certainly been told is that "PG" -- whoever that actually is -- is not willing to accept epubs nor mobis, but insists on receiving input in the form of HTML, and generating the epub and the mobi "automatically" from that HTML. In practice if one tries to submit epub or mobi one is turned away by the whitewashers, in my experience. I'm not saying that is or isn't the right policy. One might argue that epub is actually a better input format, and that html and mobi ought to be generated from epub. In practice one can get bad epub or mobi submitted, just like one can get bad html submitted. Certainly mobileread.com has lots of examples (one way or the other) where individuals have taken PG books and "improved" upon them. Again, if PG generated good guidelines for html, and/or epub and/or mobi it might be helpful -- but getting agreement on "good" guidelines is probably also difficult in practice.