It's possible for multiple things to be accurate here.
1) Orion Black felt they were not getting a level of respect they wanted, and felt stymied as a result.
2) Corporate cultures do not provide respect to contractors in general, and are slow to embrace the radical departures from standard practices/changes to norms that some contractors feel are needed/they can provide
3) Orion Black's output did not warrant extending their contract or providing them with any more deference then they received.
This isn't a scenario where WoTC is wrong, or Orion Black is wrong, and while Orion Black may feel aggrieved at the way they were treated, I don't see it as being unethical, or even anti-ethical to the message of inclusion they are embracing.