Furthermore, I have never seen any american interviewer not interrupting their subjects.
This is my bias, so I never see sexism nor racism in this context. I only see idiots who think more of themselves than they should.
In this particular case and in regards to sexism, however, the voice that should be listened to most, in my opinion, is the voice of the subject. If we don't consider her voice the most important voice we put her in the subaltern and that is the worst position you can have. The subaltern being women in the context of patriarchal history.
The person who said 'Let her speak please.', should also be heard, regardless of her motives. The interviewers should shut up and let their subjects speak at all times, so we need more of this social courage.