There is no conflict here. The quote from Github's ToS means you allow others to copy the source code you've made public, it cannot and does not give you any rights regarding what you do with the code beyond that. Points one and two of the Winamp license quote are essentially one and the same, just worded in a different way for clarity.
> If you set your pages and repositories to be viewed publicly, you grant each User of GitHub a nonexclusive, worldwide license to use, display, and perform Your Content through the GitHub Service and to reproduce Your Content solely on GitHub as permitted through GitHub's functionality (for example, through forking). You may grant further rights if you adopt a license. If you are uploading Content you did not create or own, you are responsible for ensuring that the Content you upload is licensed under terms that grant these permissions to other GitHub Users.
It would be weird to have a license that lets me create a fork in my own repo, but doesn't permit me to distribute it. If I create a fork of a public repo on GH, I require a license to distribute it because a public repo can be forked or downloaded by anyone. I can't them doing doing it. Therefore permission to further distribute is required for participation on GH.
Because if I didn't have a license then that would mean I would be liable for infringement every time someone downloaded it from GH. That's exactly why GH has the TOS that it has - so that nobody can be sued for just using GH when a rights holder uploads their own work to a public GH repo.
