If I go to https://neverssl.com/ I get a warning explaining that this site doesn't have a certificate for neverssl.com but only for Cloudfront (presumably where it's hosted)
But if I try to go to http://neverssl.com/ then I get the message explaining that the HTTPS site doesn't work, do I want the insecure HTTP one instead?
If I type "whatever.com", I'm happy with it to try port 443 first
I'm not sure if a http/80 page should be at least HEADed to see if there's a redirect to https/443 before throwing up the "this is not secure"
For those people, it makes sense that typing "http://" would take them to the "https://" site if available. Although they did specify HTTP, it isn't necessarily what they actually wanted.
I think the use case you describe (whilst valid) only applies to a relatively small pool of people. Most people don't really understand HTTP or HTTPS very well. They know it's part of the web address, and some know that "https://" is "secure", but that's about it.
I think it makes sense to direct people to the secure version of the site as much as possible, whilst of course providing a mechanism to switch to the HTTP version if necessary.
If the server says that the thing on port 80 is better served from port 443, then it can issue a 302 permanently move (and a HSTS header to make it stick). If the server offers different content on port 80 and port 443 then the server can do so just fine.
The browser should not try to second guess my explicit instructions.
Having to tell them to click through a non-https warning is almost as bad as having to tell them to click through a TLS warning.
If you offer "free" WiFi behind an annoying Captive Portal chances are I'll just use my 3G service if it works. Now, in my mind do you think I consider you offered me "free" WiFi? No, it was too annoying to use. So your competitor that didn't bother with a Captive Portal site and just posted their WiFi password on a chalkboard - they have free WiFi and you don't.