There's a difference between complaining about a class of vulnerability and exploiting a particular instance of a vulnerability that you seem to be failing to grasp.

If you find a major hole in a part of Git, you are by no means obligated to tell GitHub. You are, however, legally obligated not to compromise their site using that hole.

Or, a better example: you can talk about XSS mitigation strategies all you want. You can't go around looking for XSS vulnerabilities on random websites and then exploiting them.

"SHA1 key handling"?

Anyways, you misread him. All he's saying is that the delay Egor Homakov experienced was with the Rails dev team, not Github. Github's response to Homakov's finding was very fast.