to pretend there isn't a female biological component to their existence is madness
Nobody pretends this. Though you will find gay men who have a) been sexually harassed (and indeed straight men, as it is a power thing for men to harass others, not a sex thing) and b) who sell sex.
There is not whoever an ENTIRELY female component.
Transwomen were not brought up as girls once someone noticed their genitalia. They will not have been pressured to stay back, be quiet, not be bossy, catch more flies with honey, not be aggressive, be the peacekeepers, wear impractical clothing, play with housework toys, I could go on but I have work to do.
Transwomen have never grown breasts and been harassed for them, nor have they had periods, been afraid they were pregnant, got pregnant, miscarried, had a still birth, given birth, breastfed, had a hysterectomy, gone through menopause etc. etc.
ONE aspect of female experience that isn't even exclusive to females does not make you female.