The research you posted has been very often misquoted and is actually not relevant to the point being made that male people in the UK (the post you posted the study in reply to was UK specific, iirc).
Either way, the study you posted doesn't also mean that those male people with transgender identities should included in female single sex provisions. If they are considered by some people as 'more vulnerable to victimisation' than all other male sub groups in a population, then they and their support groups need to identify other solutions. The solution was never to allow those male people access to female single sex provisions .
However, it can also be true that a group of people are both considered vulnerable and at the very same time pose a risk to other people. It is that risk of harming others, evenly not deliberately or intentionally causing harm, that is why male people should not be included in female single sex provisions.
Here is an example of where a group of people are both vulnerable and at the same time they also pose a risk to others.
FINNISH STUDY INTO BULLYING OF ADOLESCENTS, INCLUDING THOSE WITH TRANSGENDER IDENTITIES
This is an interesting bit of information that the Biggs & North paper highlighted..
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=6182901
Transgender students reported being bullied more than their peers did, but they also admitting bullying others more. The study’s data enable victim/perpetrator ratios to be calculated. For all students in total, the ratio was 2.0; for transgender students, it was 1.4. Thus transgender students were relatively more likely to bully others (or at least to report it).
It was from this paper.
www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2020.612424/full
Transgender Identity Is Associated With Bullying Involvement Among Finnish Adolescents
Heino, Elias, Noora Ellonen, and Riittakerttu Kaltiala. 2021
Abstract
Background:
During adolescence, bullying often has a sexual content. Involvement in bullying as a bully, victim or both has been associated with a range of negative health outcomes. Transgender youth appear to face elevated rates of bullying in comparison to their mainstream peers. However, the involvement of transgender youth as perpetrators of bullying remains unclear in the recent literature.
Objective:
The aim of this study was to compare involvement in bullying between transgender and mainstream youth and among middle and late adolescents in a general population sample.
Methods:
Our study included 139,829 students in total, divided between a comprehensive school and an upper secondary education sample. Associations between gender identity and involvement in bullying were first studied using cross-tabulations with chi-square statistics. Logistic regression was used to study multivariate associations. Gender identity was used as the independent variable, with cisgender as the reference category. Subjection to and perpetration of bullying were entered each in turn as the dependent variable. Demographic factors, family characteristics, internalizing symptoms, externalizing behaviors, and involvement in bullying in the other role were added as confounding factors. Odds ratios (OR) with 95% confidence intervals (95% CI) are given. The limit for statistical significance was set at p < 0.001.
Results:
Both experiences of being bullied and perpetrating bullying were more commonly reported by transgender youth than by cisgender youth. Among transgender youth, all involvement in bullying was more commonly reported by non-binary youth than those identifying with the opposite sex. Logistic regression revealed that non-binary identity was most strongly associated with involvement in bullying, followed by opposite sex identity and cisgender identity. Transgender identities were also more strongly associated with perpetration of bullying than subjection to bullying.
Conclusion:
Transgender identity, especially non-binary identity, is associated with both being bullied and perpetrating bullying even when a range of variables including internal stress and involvement in bullying in the opposite role are taken into account. This suggests that bullying during adolescence may serve as a mechanism of maintaining heteronormativity.
Just to pull this out:
Both experiences of being bullied and perpetrating bullying were more commonly reported by transgender youth than by cisgender youth.