Perhaps one of the downvoters can explain why the implied opinion "Nobody should be able to access your site without clearance from a third-party gatekeeper" belongs on a site called "Hacker News."
And no, it won't be opt-in for long. Read the rest of the page: "Once HTTPS becomes even more widely supported by websites than it is today, we expect it will be possible for web browsers to deprecate HTTP connections and require HTTPS for all websites. In summary, HTTPS-Only Mode is the future of web browsing!"
This is something you should be speaking up against.