How is a public key revealing your identity? You can generate as many pair as you want. If you want your identity on github to be masked just generate a key specifically for github
This is all fine and well if you know that github exposes your keys. Which, at least wheb I added my keys, was not mentioned in a big, red button in the key dialog. Maybe I trusted GH too much by not creating a separate key pair for them. But information about me is being leaked without my knowledge, and that's wrong.
Yes, I for one didn't know that GitHub did this. If I had had a pseudonymous account that I trusted GitHub to protect, it would have exposed my identity because I wouldn't have realized it was important to make separate SSH keys.
Edit: Elsewhere commenters say GitHub wouldn't have allowed this for a different policy reason, so this problem couldn't actually come to pass.