>Do you feel entitled to walk into a bookstore and grab a second copy for free because you already "paid for access" to the text itself?

No because a book is an actual physical thing that costs money to produce, an ebook is not.

You have already supported the author and they are not losing anything by you downloading a different format.

Personally I think that someone having access to a book is always more valuable than a publisher getting paid, and don't see an issue with people pirating everything if it's not economically accessible. But if you feel the corporatist urge to make sure they get every cent they possibly can, go ahead.