You're making a mistake assuming that the push for HTTPS-only Web is about protecting the content of your site.
The problem is that mere existence of HTTP is a vulnerability. Users following any insecure link to anywhere allow MITM attackers to inject any content, and redirect to any URL.
These can be targeted attacks against vulnerabilities in the browser. These can be turning browsers into a botnet like the Great Cannon. These can be redirects, popunders, or other sneaky tab manipulation for opening phishing pages for other domains (unrelated to yours) that do have important content.
Your server probably won't even be contacted during such attack. Insecure URLs to your site are the vulnerability. Don't spread URLs that disable network-level security.
The problem is that mere existence of HTTP is a vulnerability. Users following any insecure link to anywhere allow MITM attackers to inject any content, and redirect to any URL.
These can be targeted attacks against vulnerabilities in the browser. These can be turning browsers into a botnet like the Great Cannon. These can be redirects, popunders, or other sneaky tab manipulation for opening phishing pages for other domains (unrelated to yours) that do have important content.
Your server probably won't even be contacted during such attack. Insecure URLs to your site are the vulnerability. Don't spread URLs that disable network-level security.