It wasn't an issue of misogyny. Meg was condescending to Prajje about racial issues when the designers received the assignment. Meg could have kept the discussion between Prajje and herself, but instead she berated and walked over Kenneth when he asked if she would be willing to trade models. Meg could have told Kenneth no and she may have been scorned, but it would have avoided the yelling match. I have no sympathy for Meg and how ungracious she was.
As for Project Runway allowing it to occur, I'll point out that none of the judges or Christian Siriano were in the design room. I don't know who else is expected to intervene. I didn't see any evidence of misogyny by the crews recording the footage.
One other thing to mention, based upon the selection and fabrics that the designers chose for the "streetwear" challenge, I can see where Meg may have had the losing look (she chose a lot of tan and khaki). If she hadn't quit, she could have been eliminated by the judges.
The person that lost out on last night's episode was the white male model that Meg exchanged with Kenneth since he most likely be chosen for any menswear challenges later in the season. It will be interesting to see if he will be available for the model call before the season finale.