The guy seems to be able to sweet talk his way in to any room and convince people to do and say the most humiliating things on camera. If him being British become an issue I think he can just act his way out of it and somehow everyone will believe him in spite of it being a publicly known fact.
I think the doughnut thing is actually just some folks wanting a laugh and trying to be witty. The phrase made sense as it was intended and was taken as such (a person from Berlin), and the fact that there is coincidentally also a doughnut given that name is unlikely to have registered in anyone’s mind while present at the speech and if it did it probably wouldn’t have merited much more than a smirk since it’s not a mistake to have said that, it’s just a funny coincidence.
I’m sure there’s probably more than one pizzeria somewhere with a pizza on the menu called “New Yorker” and if someone said in a speech “I’m a New Yorker” no one’s going to pissing themselves laughing at the person for being such a baffoon to have accidentally called themselves a pizza.