tl;dr - Oh noes, GitHub attempts to make it easy for newbs, and so I can't be smart and do things normally, despite them putting up no barriers to that!
I did then submit to hacker news on a whim, first time writing a post, next time I'll sit on a little longer and re-read it later, to make sure I've clearly made my point.
"Check for SSH keys. Have an existing key pair? You can skip to Step 4"
I think many people might not know what that means. Also, why does the next step tell you to move any key pairs you already have, if you are only supposed to do this step if you don't have a key pair?
There is a possibility I'm confused, but I think this guide assumes too much, and makes users undertake possibly dangerous changes, when the easier option (login with username/password) is much less risky.