Is there any reason to assume a conspiracy and drama around the bounty here other that just being bored and cynical? Apple has a well known security bounty program https://security.apple.com/bounty/
So the researcher didn't get a bounty from Apple then, no?
we don't know
It's not possible to apply human morale and principles to companies. It just does not work that way.
Why would they pay if no profit if pay and they are not forced to pay?
Do not fall into the trap of anthropomorphising Apple
To inspire more of the same.
Ideally Apple would incentivise people reporting security issues to them, instead of risking people selling them to someone else who pays more.