Apparently the deletion log excerpt only appears if the user is technically able to create the page.
"Unauthorized" viewers familiar with the usual behavior will either incorrectly assume that the page has never existed, or have to navigate manually to the deletion log just to be sure.
This becomes a concern for non-sysop users who clicked a red link to a protected-deleted page (or to a deleted MediaWiki namespace page), and for all users navigating to any deleted non-talk page while not logged-in.
A couple other people agreed with me that this is probably a bug rather than a helpful omission. See: