There is no such thing as this "social contract".
I publish software on github with MIT or (A)GPL licenses for various reasons:
* In case someone else has the same issue I did
* In case someone is working on something similar and wants to learn from my code
* As an external backup in addition to my hard drive / private git repo / etc.
* Because I can. (deal with it.)
There is NO expectation or "contract" or anything. People can open issues or politely request things, but getting upset or pushy over F/OSS released on someone else's own terms is just entitlement.