Comment by ecdavis

>If it's public static content, what is SSL protecting?

Plenty.

Off the top of my head:

It protects people/companies from having their reputations ruined by a MITM attack that replaces content on their site with something offensive.

It protects sensitive/important content on sites from being tampered with by an attacker. For example, if I am hosting a binary for download I can make a signature available for that binary on my site. In order for the signature to serve its purpose the user needs to be sure it hasn't been modified en route.