Isn't there a dedicated site called nohttps or something? NeverSSL? I just tried http NeverSSL, and it redirected me to an https page with a random hostname and an Amazon SSL certificate!
Does example.com still function this way, with http and no HSTS? I noticed that my Chrome browser was immediately redirected in the customary way.
Are you perhaps on an untrusted network which is spoofing that url to make it redirect somewhere else?
If this is a joke, it's over my head. If not, I'm not knowledgeable enough in this space to pass judgement, but that would seem crazy to me. Like the owner should consider a domain name change :)
Kinda weird setup!
Edit: okay, the subdomains also have SSL. I guess the random subdomain thing is to make sure it hasn’t been cached in a “this site has HTTPS” list. The HTTPS is needed, of course, to please the browser makers, as the parent says.
This is very useful, thanks for sharing!