The difference, to me, is what a transgender person is supposed to represent in the ad. If Mulvaney, for example, was used in a beer ad to represent the transgender market for that beer, fine.
If it's something specifically about one sex, such as menstruation, and the transgender person used in the ad is male, I would need a much stronger reason why someone to whom the product doesn't matter should take that role.
Why would a male person advertise period products, for example? Should we use a trans man, a female person, to speak about prostate cancer?
Women get angry because much of this is a forced redefinition of who we are, who we have always lived as, and when we complain about that we are called bigots. So accept that 'woman' now means a bundle of sexist stereotypes about femininity, accept that your own embodied identity as a woman is now invalid, or be regarded as something heinous.
And that new definition of 'woman' will make it extremely hard to do feminist work fighting against sex-based oppression as we will no longer even be able to define the victim group it affects.