I think in Ellen’s mind she’s demonstrating how she’s a gutsy no-nonsense broad of the ilk of Katherine Hepburn that owns her power and star quality or some such, and isn’t star-struck by male celebrity, but in reality she’s just outing herself as an entitled actor who enjoys the feeling of holding a show to ransom. Asshole be deluded about her place but I don’t think it’s necessarily racism: she just likes throwing her weight around with everyone. If the director had been anyone of any standing they would have been well within their rights to express annoyance at being undermined, especially if they’d been specifically asked to take the role of purveyor of artistic vision for an episode. How embarrassing for Shonda and others excited to have him there and the kind woman who arranged it. Some people don’t know how to behave.