No-one on Mumsnet demonises everyone who identifies as the opposite sex.
For example, many female children who identify as boys, primarily do so, because they are frightened they might be same-sex attracted. Or they hope to escape the male gaze/attention from creepy men that starts at puberty. Or they are trying to make sense of the world as a bullied autistic child. It may even be a response to childhood sexual abuse, or to escape continuing abuse.
Feeling compassion and wanting appropriate support (including criminal justice/police involvement where appropriate) for these girls is a natural human response.
This support should include encouraging the girls to feel more comfortable in their female bodies and to overcome any homophobia or bullying they may have suffered. Being same-sex attracted is absolutely fine, it does not mean you are really a boy. And the shame of sexual abuse falls only on the perpetrator.
Encouraging children to believe they can change sex is an additional cruelty. It will make their adult lives smaller, sadder and much more complex. Living a lie is exhausting.
One of the many problems with 'Gender Ideology' is that by pushing males into women-only spaces it makes women and girls feel unsafe. And these women and girls respond by not coming back. Teenage girls stop playing football. Elderly women stop relaxing at their so-called women's pond. No-one dares complain and be labelled transphobic.
Thus, by including trans women and trans girls (legally men and boys respectively under the Equality Act 2010) you're actively choosing to exclude women and girls.
Including trans women means excluding women. That's the choice you're making. Be honest. Own (up to) your decisions.
Why prioritise the wants of men and boys over the needs of women and girls?
Why support medical professionals lying to vulnerable children and damaging their ability to have a full, independent and joyful adult life?
These are very bad choices. Please think again.