For me,
the point that could be against ebooks is the risk of alteration of content.
A printed book is printed once for all, and unless we consider the source as questionable, the content can't be altered.
It's too easy to alter the content of an ebook, and I fear the self-righteous that could modify a book to "protect" me from "dubious", "immoral", or any other "bad" content.
Just my opinion.
That's the point anti-ebook people could lean on, and that point is a good one to approve DRM... Don't throw stones, please !