bbPress.org

Even though you have some influence over what they decide to do, this update is very simple and the right thing to do.
Browsers flag all http sites as unsafe, so I believe 21% of http sites are essentially abandoned.
Since 79% of sites are http, it’s logical that if a site doesn’t specify https, it’s a given that https will be prefixed instead of http.
Or, they could just as easily leave the www without the http(s) in front.