What sick means is defined by outcomes, as cited in the quote you pointed out yourself.

> mental health impacts, especially in young people; violence against women, girls, and gender minorities; and delegitimising help-seeking in boys and men

These are real life, observable, negative public health outcomes.

They don't need anyone to define them, they just are. The ideologically inconvenient thing is that some people's identity is tied up with the causes of above negative outcomes, causing them to violently reject critical examination.