It is sexist. Mayer's appearance has nothing to do with the context of the video and focusing on it perpetuates the double standards about what we expect of men

It is sexist. Mayer's appearance has nothing to do with the context of the video and focusing on it perpetuates the double standards about what we expect of men in terms of appearance, effort towards it, dress, etc and what we expect of women in the same. Mentioning it implies it's something worth mentioning. It isn't, for either men or women. The trick is it's self evident that mentioning it for men would be irrelevant. For some reason, however, people take issue with someone pointing out that it ought to be irrelevant for women.