There's mobile-friendly, and there's mobile UNfriendly.
I can demonstrate objectively that some web pages don't work on mobile devices, even iPads and large Android or Windows tablets. Anything that relies on the mouse hovering over an object to activate it (like a lot of sites do with navigation menus) is going to fail. Yahoo's login page used to fail on mobile browsers; it kept "centering" the login box, but on a mobile browser, that kept shoving it off the right side of the screen.
And this site gets all messed up on my iPad... I can't log in to at all on Chrome and the layout gets all weird on Safari.
It's one thing to optimize pages for small screens. However, every web site should at least work on a touch device, and right now that's not still the case.