A lot of prior military folks will use males and females just because that’s how it’s been drilled into them. Male and female latrines, not men and women’s bathrooms. Male and female barracks, not men and women’s dorms. Male and female standards, etc etc.
Technically the triangle just refers to ‘relationships’ and not ‘romantic relationships’ so two male friends and one female love interest works as a triangle but one woman with two male strangers doesn’t with because that’s just a V.