It's not the same in e.g. Russia (and I'm sure it's not just Russia). In Russia, the Web is now officially being censored by the state. They have a national register of prohibited resources -- basically, a huge list of URLs. Every ISP must block all access to those URLs, or else.
So if a page (perhaps, a comment page?) on your site enters the register, and it is served over unencrypted HTTP, ISPs can use DPI to block the access to just that specific page -- which sucks, but at least your site is still accessible. If, however, you use HTTPS -- then ISPs have no other choice but to block all traffic to your site entirely. Given that choice, many webmasters (myself included) will have to choose plain HTTP.