GitHub doesn't take any more setup than a standard Git setup takes (well, outside of signing up, a very short process anyhow). Install the Git client via the Windows installer, (point and click, a minute, tops). Generate an SSH key. Upload the id_rsa.pub. Done. I mean, it would be one thing if they left users in the dark about this, but I'm fairly sure that the "Thanks for signing up page" links directly to the OS-specific meticulous step-by-step instructions of generating the key.
I'm not sure you understand what it means to be flamed. Every one of the comments is specific about your misconceptions and why signing up for a GitHub account is as trivially easy as signing up for a Twitter account. (Using GitHub as an oAuth account does not require actually uploading a public key)