[comex]

It may be the case that what the license permits (combined with fair use law) is sufficient to allow what GitHub actually, currently does with the code, but not everything their TOS claims the right to do.

In particular, "store and display your Content [..] as necessary to render the Website and provide the Service" is rather broad given that the functionality included in the "Service" (defined as "the applications, software, products, and services provided by GitHub") can change at any time, without notice.