It’s not for protecting OPF or hiding content from Google or anyone else. HTTPS is used more often by webusers than the original non-secure HTTP, primarily to protect page authenticity on all types of websites; secure accounts; and keep user communications, identity, and web browsing private (Words from Wikipedia). The thing is that since https is being mandated now, the user experience of websites will be affected and when people turn away from sites when they see that it is not secure, that will affect OPF as well.
True not everyone uses Chrome browser, but according to stats counters, around 60% of desktop and mobile web browsing is with Chrome. Even on tablets as high a 40%. That aside, Safari and Firefox and probably before long, the others - are following the standard of providing Not Secure warnings for non https sites or ones that include log in forms from nine https.
It’s really that we website owners have no choice but to switch, if we want people to visit our website. A lot of business websites include Google maps of their location on their Contact Page. That can no longer be done on a non-secure http website.