Earlier quoted context omitted.
I don't know why it is just GPL people talk about. MPL, Apache, MIT licenses all have additional terms beyond a basic public domain equivalent license. None of those terms are being respected.
If you upload it to github, you give microsoft extra rights above the license you choose. I'm not sure they are bound by the license.
What happens if someone else uploads my code to github?
What happens if proprietary code is uploaded to github?
What happens if national secrets are posted to github?
In all of those cases, the person doing the upload does not "own" the content, nor did they choose the license.
There is no reasonable read of a ToS agreement that would allow Microsoft/Github extra rights to that content.