This isn't new. People have been saying this about Michelle Obama since her husband first ran for president. Many tall, muscular Black cisgender women are accused of being men. This is known as misogynoir.

Of course, trans and intersex women are also falsely accused of being men, particularly women of color. Misogynoir and transmisogyny harms trans and cis women alike, as it's all rooted in the policing of women's bodies.

P.S. I'm not a Democrat, either; I belong to no political party.