Freddy Krueger Was the Prom Queen
There is more than one way to be a man, but only one categorical way to be a cisman. Men who dress like Strawberry Shortcake for a hobby are too sweet to be cismen. They have no manly peers who don't crossdress and who self-identify with them. Their only potential peers are other men who crossdress. So, will the real cismen please stand up? If you have to smooth out your skirt when you leave your chair then you should definitely sit back down.
Transgender people come in different stripes but they all have stripes. They range from multiple types of transmen to multiple types of transwomen. Being transgender is about being something and not being something else. The something else that transgender people are not is cismasculine cismales or cisfeminine cisfemales. All other grades of sex and gender combination that don't involve these four attributes are possible. Some transmen were born with female genitals. Some transmen were born with male genitals, like to wear prom dresses, and give long boring speeches about how trivial their dresses are compared to the significant dresses worn by real women. It's still possible to be a transman in this sense (using the last word loosely).