But the crux of the disagreement is that if you are essentially serving the same content to everyone, then there is no reason to use https
This is not true. The main purpose of using HTTPS is to protect the user of your website.

Without HTTPS, users are vulnerable to MITM attacks. What if a malicious entity intercepted the user's request to your simple website? What if instead of returning your simple website to the user, they returned a malicous copy that attempted to install malware? What if it added a donation box that would send money to the attacker? What if it added a "log in via Facebook" link to the top of your page, but the credentials went to the attacker instead? Javascript is very powerful, and there are a lot of things a bad site can do to steal information or exploit vulnerabilities.

In my opinion, the only valid reason for not using HTTPS is the cost factor. Chrome has already stated that sometime in 2015 it will explicitly mark HTTP websites as insecure as a warning to the user.